commit 9a83c7feeee37fabd4382f5161a6248771c6fcfb Author: Nils Briggen Date: Fri Aug 7 23:32:17 2026 +0200 docs: add project brief, invariants, mistakes log, and GPL-3.0-or-later licence Licence decided 2026-08-07: GPL-3.0-or-later, superseding the tentative MPL-2.0 in the brief. Copyleft chosen knowingly: forks stay open, proprietary plugins are off the table. Compatible with OCCT's LGPL-2.1-with-exception. Co-Authored-By: Claude Fable 5 diff --git a/CLAUDE.md b/CLAUDE.md new file mode 100644 index 0000000..4acd43c --- /dev/null +++ b/CLAUDE.md @@ -0,0 +1,150 @@ +# CLAUDE.md — VernierCAD + +Parametric 3D CAD. Rust, OCCT kernel via `cxx`, wgpu render, egui shell, Linux-native. + +Product name is **VernierCAD**; crate prefix, binary, and repo are plain `vernier`. Use +"VernierCAD" in user-facing strings, docs, and the window title. Use `vernier` everywhere +in code. + +Read `PROJECT_BRIEF.md` before your first substantial change. Read `MISTAKES.md` before +debugging anything that smells familiar. + +**Current phase: 0 — Foundation.** Nothing below Phase 0 in the brief exists yet. If asked +to build something from a later phase, say so and confirm before starting. + +--- + +## Hard invariants + +Violating any of these is a bug even if tests pass. + +1. **Determinism is mandatory.** Same input → byte-identical output. No `HashMap` iteration + where order reaches output; use `IndexMap` or sort. No time, no RNG, no address-dependent + ordering, no float accumulation whose order varies with thread scheduling. If you cannot + make an operation deterministic, stop and raise it. + +2. **`vernier-occt-sys` is the only crate permitted `unsafe`.** Every other crate carries + `#![forbid(unsafe_code)]`. No exceptions without discussion. + +3. **Every kernel operation returns a history delta.** An operation that returns a bare + shape is incomplete. See `OpResult` in `vernier-kernel`. + +4. **Entity identity never derives from index or pointer.** `EntityId` is allocated by + `vernier-doc` and mapped through the façade. If you find yourself writing + `shape.face(3)` in Rust, you have made a mistake. + +5. **Never silently resolve an ambiguous topological reference.** Below the fingerprint + confidence threshold, mark the reference broken and surface it. A wrong-but-plausible + face assignment is worse than an error, because the user ships the part. + +6. **The render thread never blocks on the kernel.** Kernel work runs on a worker. The + viewport orbits at refresh rate during an eight-second recompute or the design is wrong. + +7. **No feature is finished without a headless test.** If it cannot be exercised through + `vernier-cli` with no display, it is not done. + +8. **Units are millimetres, floats are `f64`, angles are radians internally.** Degrees only + at the UI boundary. + +9. **Target GPU is AMD RX 7800 XT (RDNA3, Mesa/RADV).** Never write NVIDIA-specific code or + suggest CUDA. Validate against Vulkan via RADV. + +10. **Scope is Section 1 of the brief.** No CAM, no simulation, no cloud, no sheet metal. + Decline and say why. + +## Crate map + +``` +vernier-occt-sys/ cxx bridge + facade.cpp [unsafe allowed] +vernier-kernel/ trait Kernel, OpResult, EntityId, OCCT impl +vernier-solver/ 2D constraint solver [no kernel dep] +vernier-doc/ feature DAG, undo, serde [no kernel dep] +vernier-tess/ tessellation + cache +vernier-render/ wgpu, ID-buffer picking +vernier-ui/ egui shell, viewport, timeline +vernier-cli/ headless driver +vernier-app/ thin main() +``` + +Dependencies point downward only. `vernier-solver` and `vernier-doc` importing `vernier-kernel` +is a design failure, not a convenience. If a task seems to require it, the abstraction is +wrong — raise it rather than adding the dependency. + +## Commands + +Shell is **fish**. No bash heredocs. No `export VAR=x` — use `set -x`. Write files with +`printf` or multi-line `echo`, not `cat <` never crosses the FFI boundary. Ever. +- Every façade function that creates or modifies a shape also returns its history +- All OCCT exceptions are caught in C++ and converted to result codes. An OCCT exception + crossing into Rust is undefined behaviour and will eventually corrupt something quietly. +- `facade.hpp` is the complete API surface. If a new OCCT capability is needed, it gets a + new façade function — not a leaked type. + +## Working agreements + +- When an invariant above seems wrong for the task at hand, **say so and stop.** Do not + route around it, do not add a local exception, do not `#[allow]` it. The invariants are + load-bearing; if one is wrong it needs changing here, not bypassing there. +- When a bug costs more than an hour, add an entry to `MISTAKES.md`: symptom, root cause, + the wrong hypothesis that wasted the time. +- Explain *why* alongside any non-obvious change. Directional effects, not just the diff. +- Prefer showing a small example over describing the approach. +- Push back on bad instructions. Being agreeable about a design error is not helpful. +- Do not add dependencies without asking. The dependency tree is a maintenance liability + and this project outlives most crates. +- Do not write speculative abstraction for phases that do not exist yet. diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..f288702 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +them if you wish), that you receive source code or can get it if you +want it, that you can change the software or use pieces of it in new +free programs, and that you know you can do these things. + + To protect your rights, we need to prevent others from denying you +these rights or asking you to surrender the rights. Therefore, you have +certain responsibilities if you distribute copies of the software, or if +you modify it: responsibilities to respect the freedom of others. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must pass on to the recipients the same +freedoms that you received. You must make sure that they, too, receive +or can get the source code. And you must show them these terms so they +know their rights. + + Developers that use the GNU GPL protect your rights with two steps: +(1) assert copyright on the software, and (2) offer you this License +giving you legal permission to copy, distribute and/or modify it. + + For the developers' and authors' protection, the GPL clearly explains +that there is no warranty for this free software. For both users' and +authors' sake, the GPL requires that modified versions be marked as +changed, so that their problems will not be attributed erroneously to +authors of previous versions. + + Some devices are designed to deny users access to install or run +modified versions of the software inside them, although the manufacturer +can do so. This is fundamentally incompatible with the aim of +protecting users' freedom to change the software. The systematic +pattern of such abuse occurs in the area of products for individuals to +use, which is precisely where it is most unacceptable. Therefore, we +have designed this version of the GPL to prohibit the practice for those +products. If such problems arise substantially in other domains, we +stand ready to extend this provision to those domains in future versions +of the GPL, as needed to protect the freedom of users. + + Finally, every program is threatened constantly by software patents. +States should not allow patents to restrict development and use of +software on general-purpose computers, but in those that do, we wish to +avoid the special danger that patents applied to a free program could +make it effectively proprietary. To prevent this, the GPL assures that +patents cannot be used to render the program non-free. + + The precise terms and conditions for copying, distribution and +modification follow. + + TERMS AND CONDITIONS + + 0. Definitions. + + "This License" refers to version 3 of the GNU General Public License. + + "Copyright" also means copyright-like laws that apply to other kinds of +works, such as semiconductor masks. + + "The Program" refers to any copyrightable work licensed under this +License. Each licensee is addressed as "you". "Licensees" and +"recipients" may be individuals or organizations. + + To "modify" a work means to copy from or adapt all or part of the work +in a fashion requiring copyright permission, other than the making of an +exact copy. The resulting work is called a "modified version" of the +earlier work or a work "based on" the earlier work. + + A "covered work" means either the unmodified Program or a work based +on the Program. + + To "propagate" a work means to do anything with it that, without +permission, would make you directly or secondarily liable for +infringement under applicable copyright law, except executing it on a +computer or modifying a private copy. Propagation includes copying, +distribution (with or without modification), making available to the +public, and in some countries other activities as well. + + To "convey" a work means any kind of propagation that enables other +parties to make or receive copies. Mere interaction with a user through +a computer network, with no transfer of a copy, is not conveying. + + An interactive user interface displays "Appropriate Legal Notices" +to the extent that it includes a convenient and prominently visible +feature that (1) displays an appropriate copyright notice, and (2) +tells the user that there is no warranty for the work (except to the +extent that warranties are provided), that licensees may convey the +work under this License, and how to view a copy of this License. If +the interface presents a list of user commands or options, such as a +menu, a prominent item in the list meets this criterion. + + 1. Source Code. + + The "source code" for a work means the preferred form of the work +for making modifications to it. "Object code" means any non-source +form of a work. + + A "Standard Interface" means an interface that either is an official +standard defined by a recognized standards body, or, in the case of +interfaces specified for a particular programming language, one that +is widely used among developers working in that language. + + The "System Libraries" of an executable work include anything, other +than the work as a whole, that (a) is included in the normal form of +packaging a Major Component, but which is not part of that Major +Component, and (b) serves only to enable use of the work with that +Major Component, or to implement a Standard Interface for which an +implementation is available to the public in source code form. A +"Major Component", in this context, means a major essential component +(kernel, window system, and so on) of the specific operating system +(if any) on which the executable work runs, or a compiler used to +produce the work, or an object code interpreter used to run it. + + The "Corresponding Source" for a work in object code form means all +the source code needed to generate, install, and (for an executable +work) run the object code and to modify the work, including scripts to +control those activities. However, it does not include the work's +System Libraries, or general-purpose tools or generally available free +programs which are used unmodified in performing those activities but +which are not part of the work. For example, Corresponding Source +includes interface definition files associated with source files for +the work, and the source code for shared libraries and dynamically +linked subprograms that the work is specifically designed to require, +such as by intimate data communication or control flow between those +subprograms and other parts of the work. + + The Corresponding Source need not include anything that users +can regenerate automatically from other parts of the Corresponding +Source. + + The Corresponding Source for a work in source code form is that +same work. + + 2. Basic Permissions. + + All rights granted under this License are granted for the term of +copyright on the Program, and are irrevocable provided the stated +conditions are met. This License explicitly affirms your unlimited +permission to run the unmodified Program. The output from running a +covered work is covered by this License only if the output, given its +content, constitutes a covered work. This License acknowledges your +rights of fair use or other equivalent, as provided by copyright law. + + You may make, run and propagate covered works that you do not +convey, without conditions so long as your license otherwise remains +in force. You may convey covered works to others for the sole purpose +of having them make modifications exclusively for you, or provide you +with facilities for running those works, provided that you comply with +the terms of this License in conveying all material for which you do +not control copyright. Those thus making or running the covered works +for you must do so exclusively on your behalf, under your direction +and control, on terms that prohibit them from making any copies of +your copyrighted material outside their relationship with you. + + Conveying under any other circumstances is permitted solely under +the conditions stated below. Sublicensing is not allowed; section 10 +makes it unnecessary. + + 3. Protecting Users' Legal Rights From Anti-Circumvention Law. + + No covered work shall be deemed part of an effective technological +measure under any applicable law fulfilling obligations under article +11 of the WIPO copyright treaty adopted on 20 December 1996, or +similar laws prohibiting or restricting circumvention of such +measures. + + When you convey a covered work, you waive any legal power to forbid +circumvention of technological measures to the extent such circumvention +is effected by exercising rights under this License with respect to +the covered work, and you disclaim any intention to limit operation or +modification of the work as a means of enforcing, against the work's +users, your or third parties' legal rights to forbid circumvention of +technological measures. + + 4. Conveying Verbatim Copies. + + You may convey verbatim copies of the Program's source code as you +receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy an appropriate copyright notice; +keep intact all notices stating that this License and any +non-permissive terms added in accord with section 7 apply to the code; +keep intact all notices of the absence of any warranty; and give all +recipients a copy of this License along with the Program. + + You may charge any price or no price for each copy that you convey, +and you may offer support or warranty protection for a fee. + + 5. Conveying Modified Source Versions. + + You may convey a work based on the Program, or the modifications to +produce it from the Program, in the form of source code under the +terms of section 4, provided that you also meet all of these conditions: + + a) The work must carry prominent notices stating that you modified + it, and giving a relevant date. + + b) The work must carry prominent notices stating that it is + released under this License and any conditions added under section + 7. This requirement modifies the requirement in section 4 to + "keep intact all notices". + + c) You must license the entire work, as a whole, under this + License to anyone who comes into possession of a copy. This + License will therefore apply, along with any applicable section 7 + additional terms, to the whole of the work, and all its parts, + regardless of how they are packaged. This License gives no + permission to license the work in any other way, but it does not + invalidate such permission if you have separately received it. + + d) If the work has interactive user interfaces, each must display + Appropriate Legal Notices; however, if the Program has interactive + interfaces that do not display Appropriate Legal Notices, your + work need not make them do so. + + A compilation of a covered work with other separate and independent +works, which are not by their nature extensions of the covered work, +and which are not combined with it such as to form a larger program, +in or on a volume of a storage or distribution medium, is called an +"aggregate" if the compilation and its resulting copyright are not +used to limit the access or legal rights of the compilation's users +beyond what the individual works permit. Inclusion of a covered work +in an aggregate does not cause this License to apply to the other +parts of the aggregate. + + 6. Conveying Non-Source Forms. + + You may convey a covered work in object code form under the terms +of sections 4 and 5, provided that you also convey the +machine-readable Corresponding Source under the terms of this License, +in one of these ways: + + a) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by the + Corresponding Source fixed on a durable physical medium + customarily used for software interchange. + + b) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by a + written offer, valid for at least three years and valid for as + long as you offer spare parts or customer support for that product + model, to give anyone who possesses the object code either (1) a + copy of the Corresponding Source for all the software in the + product that is covered by this License, on a durable physical + medium customarily used for software interchange, for a price no + more than your reasonable cost of physically performing this + conveying of source, or (2) access to copy the + Corresponding Source from a network server at no charge. + + c) Convey individual copies of the object code with a copy of the + written offer to provide the Corresponding Source. This + alternative is allowed only occasionally and noncommercially, and + only if you received the object code with such an offer, in accord + with subsection 6b. + + d) Convey the object code by offering access from a designated + place (gratis or for a charge), and offer equivalent access to the + Corresponding Source in the same way through the same place at no + further charge. You need not require recipients to copy the + Corresponding Source along with the object code. If the place to + copy the object code is a network server, the Corresponding Source + may be on a different server (operated by you or a third party) + that supports equivalent copying facilities, provided you maintain + clear directions next to the object code saying where to find the + Corresponding Source. Regardless of what server hosts the + Corresponding Source, you remain obligated to ensure that it is + available for as long as needed to satisfy these requirements. + + e) Convey the object code using peer-to-peer transmission, provided + you inform other peers where the object code and Corresponding + Source of the work are being offered to the general public at no + charge under subsection 6d. + + A separable portion of the object code, whose source code is excluded +from the Corresponding Source as a System Library, need not be +included in conveying the object code work. + + A "User Product" is either (1) a "consumer product", which means any +tangible personal property which is normally used for personal, family, +or household purposes, or (2) anything designed or sold for incorporation +into a dwelling. In determining whether a product is a consumer product, +doubtful cases shall be resolved in favor of coverage. For a particular +product received by a particular user, "normally used" refers to a +typical or common use of that class of product, regardless of the status +of the particular user or of the way in which the particular user +actually uses, or expects or is expected to use, the product. A product +is a consumer product regardless of whether the product has substantial +commercial, industrial or non-consumer uses, unless such uses represent +the only significant mode of use of the product. + + "Installation Information" for a User Product means any methods, +procedures, authorization keys, or other information required to install +and execute modified versions of a covered work in that User Product from +a modified version of its Corresponding Source. The information must +suffice to ensure that the continued functioning of the modified object +code is in no case prevented or interfered with solely because +modification has been made. + + If you convey an object code work under this section in, or with, or +specifically for use in, a User Product, and the conveying occurs as +part of a transaction in which the right of possession and use of the +User Product is transferred to the recipient in perpetuity or for a +fixed term (regardless of how the transaction is characterized), the +Corresponding Source conveyed under this section must be accompanied +by the Installation Information. But this requirement does not apply +if neither you nor any third party retains the ability to install +modified object code on the User Product (for example, the work has +been installed in ROM). + + The requirement to provide Installation Information does not include a +requirement to continue to provide support service, warranty, or updates +for a work that has been modified or installed by the recipient, or for +the User Product in which it has been modified or installed. Access to a +network may be denied when the modification itself materially and +adversely affects the operation of the network or violates the rules and +protocols for communication across the network. + + Corresponding Source conveyed, and Installation Information provided, +in accord with this section must be in a format that is publicly +documented (and with an implementation available to the public in +source code form), and must require no special password or key for +unpacking, reading or copying. + + 7. Additional Terms. + + "Additional permissions" are terms that supplement the terms of this +License by making exceptions from one or more of its conditions. +Additional permissions that are applicable to the entire Program shall +be treated as though they were included in this License, to the extent +that they are valid under applicable law. If additional permissions +apply only to part of the Program, that part may be used separately +under those permissions, but the entire Program remains governed by +this License without regard to the additional permissions. + + When you convey a copy of a covered work, you may at your option +remove any additional permissions from that copy, or from any part of +it. (Additional permissions may be written to require their own +removal in certain cases when you modify the work.) You may place +additional permissions on material, added by you to a covered work, +for which you have or can give appropriate copyright permission. + + Notwithstanding any other provision of this License, for material you +add to a covered work, you may (if authorized by the copyright holders of +that material) supplement the terms of this License with terms: + + a) Disclaiming warranty or limiting liability differently from the + terms of sections 15 and 16 of this License; or + + b) Requiring preservation of specified reasonable legal notices or + author attributions in that material or in the Appropriate Legal + Notices displayed by works containing it; or + + c) Prohibiting misrepresentation of the origin of that material, or + requiring that modified versions of such material be marked in + reasonable ways as different from the original version; or + + d) Limiting the use for publicity purposes of names of licensors or + authors of the material; or + + e) Declining to grant rights under trademark law for use of some + trade names, trademarks, or service marks; or + + f) Requiring indemnification of licensors and authors of that + material by anyone who conveys the material (or modified versions of + it) with contractual assumptions of liability to the recipient, for + any liability that these contractual assumptions directly impose on + those licensors and authors. + + All other non-permissive additional terms are considered "further +restrictions" within the meaning of section 10. If the Program as you +received it, or any part of it, contains a notice stating that it is +governed by this License along with a term that is a further +restriction, you may remove that term. If a license document contains +a further restriction but permits relicensing or conveying under this +License, you may add to a covered work material governed by the terms +of that license document, provided that the further restriction does +not survive such relicensing or conveying. + + If you add terms to a covered work in accord with this section, you +must place, in the relevant source files, a statement of the +additional terms that apply to those files, or a notice indicating +where to find the applicable terms. + + Additional terms, permissive or non-permissive, may be stated in the +form of a separately written license, or stated as exceptions; +the above requirements apply either way. + + 8. Termination. + + You may not propagate or modify a covered work except as expressly +provided under this License. Any attempt otherwise to propagate or +modify it is void, and will automatically terminate your rights under +this License (including any patent licenses granted under the third +paragraph of section 11). + + However, if you cease all violation of this License, then your +license from a particular copyright holder is reinstated (a) +provisionally, unless and until the copyright holder explicitly and +finally terminates your license, and (b) permanently, if the copyright +holder fails to notify you of the violation by some reasonable means +prior to 60 days after the cessation. + + Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + + Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. If your rights have been terminated and not permanently +reinstated, you do not qualify to receive new licenses for the same +material under section 10. + + 9. Acceptance Not Required for Having Copies. + + You are not required to accept this License in order to receive or +run a copy of the Program. Ancillary propagation of a covered work +occurring solely as a consequence of using peer-to-peer transmission +to receive a copy likewise does not require acceptance. However, +nothing other than this License grants you permission to propagate or +modify any covered work. These actions infringe copyright if you do +not accept this License. Therefore, by modifying or propagating a +covered work, you indicate your acceptance of this License to do so. + + 10. Automatic Licensing of Downstream Recipients. + + Each time you convey a covered work, the recipient automatically +receives a license from the original licensors, to run, modify and +propagate that work, subject to this License. You are not responsible +for enforcing compliance by third parties with this License. + + An "entity transaction" is a transaction transferring control of an +organization, or substantially all assets of one, or subdividing an +organization, or merging organizations. If propagation of a covered +work results from an entity transaction, each party to that +transaction who receives a copy of the work also receives whatever +licenses to the work the party's predecessor in interest had or could +give under the previous paragraph, plus a right to possession of the +Corresponding Source of the work from the predecessor in interest, if +the predecessor has it or can get it with reasonable efforts. + + You may not impose any further restrictions on the exercise of the +rights granted or affirmed under this License. For example, you may +not impose a license fee, royalty, or other charge for exercise of +rights granted under this License, and you may not initiate litigation +(including a cross-claim or counterclaim in a lawsuit) alleging that +any patent claim is infringed by making, using, selling, offering for +sale, or importing the Program or any portion of it. + + 11. Patents. + + A "contributor" is a copyright holder who authorizes use under this +License of the Program or a work on which the Program is based. The +work thus licensed is called the contributor's "contributor version". + + A contributor's "essential patent claims" are all patent claims +owned or controlled by the contributor, whether already acquired or +hereafter acquired, that would be infringed by some manner, permitted +by this License, of making, using, or selling its contributor version, +but do not include claims that would be infringed only as a +consequence of further modification of the contributor version. For +purposes of this definition, "control" includes the right to grant +patent sublicenses in a manner consistent with the requirements of +this License. + + Each contributor grants you a non-exclusive, worldwide, royalty-free +patent license under the contributor's essential patent claims, to +make, use, sell, offer for sale, import and otherwise run, modify and +propagate the contents of its contributor version. + + In the following three paragraphs, a "patent license" is any express +agreement or commitment, however denominated, not to enforce a patent +(such as an express permission to practice a patent or covenant not to +sue for patent infringement). To "grant" such a patent license to a +party means to make such an agreement or commitment not to enforce a +patent against the party. + + If you convey a covered work, knowingly relying on a patent license, +and the Corresponding Source of the work is not available for anyone +to copy, free of charge and under the terms of this License, through a +publicly available network server or other readily accessible means, +then you must either (1) cause the Corresponding Source to be so +available, or (2) arrange to deprive yourself of the benefit of the +patent license for this particular work, or (3) arrange, in a manner +consistent with the requirements of this License, to extend the patent +license to downstream recipients. "Knowingly relying" means you have +actual knowledge that, but for the patent license, your conveying the +covered work in a country, or your recipient's use of the covered work +in a country, would infringe one or more identifiable patents in that +country that you have reason to believe are valid. + + If, pursuant to or in connection with a single transaction or +arrangement, you convey, or propagate by procuring conveyance of, a +covered work, and grant a patent license to some of the parties +receiving the covered work authorizing them to use, propagate, modify +or convey a specific copy of the covered work, then the patent license +you grant is automatically extended to all recipients of the covered +work and works based on it. + + A patent license is "discriminatory" if it does not include within +the scope of its coverage, prohibits the exercise of, or is +conditioned on the non-exercise of one or more of the rights that are +specifically granted under this License. You may not convey a covered +work if you are a party to an arrangement with a third party that is +in the business of distributing software, under which you make payment +to the third party based on the extent of your activity of conveying +the work, and under which the third party grants, to any of the +parties who would receive the covered work from you, a discriminatory +patent license (a) in connection with copies of the covered work +conveyed by you (or copies made from those copies), or (b) primarily +for and in connection with specific products or compilations that +contain the covered work, unless you entered into that arrangement, +or that patent license was granted, prior to 28 March 2007. + + Nothing in this License shall be construed as excluding or limiting +any implied license or other defenses to infringement that may +otherwise be available to you under applicable patent law. + + 12. No Surrender of Others' Freedom. + + If conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot convey a +covered work so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you may +not convey it at all. For example, if you agree to terms that obligate you +to collect a royalty for further conveying from those to whom you convey +the Program, the only way you could satisfy both those terms and this +License would be to refrain entirely from conveying the Program. + + 13. Use with the GNU Affero General Public License. + + Notwithstanding any other provision of this License, you have +permission to link or combine any covered work with a work licensed +under version 3 of the GNU Affero General Public License into a single +combined work, and to convey the resulting work. The terms of this +License will continue to apply to the part which is the covered work, +but the special requirements of the GNU Affero General Public License, +section 13, concerning interaction through a network will apply to the +combination as such. + + 14. Revised Versions of this License. + + The Free Software Foundation may publish revised and/or new versions of +the GNU General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + + Each version is given a distinguishing version number. If the +Program specifies that a certain numbered version of the GNU General +Public License "or any later version" applies to it, you have the +option of following the terms and conditions either of that numbered +version or of any later version published by the Free Software +Foundation. If the Program does not specify a version number of the +GNU General Public License, you may choose any version ever published +by the Free Software Foundation. + + If the Program specifies that a proxy can decide which future +versions of the GNU General Public License can be used, that proxy's +public statement of acceptance of a version permanently authorizes you +to choose that version for the Program. + + Later license versions may give you additional or different +permissions. However, no additional obligations are imposed on any +author or copyright holder as a result of your choosing to follow a +later version. + + 15. Disclaimer of Warranty. + + THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY +OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM +IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF +ALL NECESSARY SERVICING, REPAIR OR CORRECTION. + + 16. Limitation of Liability. + + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS +THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY +GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE +USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF +DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD +PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), +EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF +SUCH DAMAGES. + + 17. Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/MISTAKES.md b/MISTAKES.md new file mode 100644 index 0000000..22626bc --- /dev/null +++ b/MISTAKES.md @@ -0,0 +1,57 @@ +# MISTAKES.md + +Bugs that cost more than an hour. Read before debugging anything that feels familiar. + +**Format:** symptom → root cause → the wrong hypothesis that wasted the time. + +The third field matters most. Knowing the answer helps once; knowing which plausible wrong +turn to skip helps every time. + +--- + +## Pre-seeded — known traps, not yet hit + +These are documented in advance because they are near-certain and expensive. + +### OCCT exception crosses the FFI boundary + +- **Symptom:** silent memory corruption, or a crash far from the actual call, often much later +- **Cause:** `Standard_Failure` unwinding through `cxx` into Rust is undefined behaviour +- **Wrong hypothesis to skip:** "the Rust side has a lifetime bug." It does not. Check that + every façade function wraps its OCCT calls in `try { } catch (Standard_Failure&)`. + +### Boolean produces a valid-looking shape with zero volume + +- **Symptom:** operation succeeds, render shows nothing or shows garbage +- **Cause:** coincident or near-coincident faces below OCCT's tolerance; the fuzzy boolean + parameter was not set +- **Wrong hypothesis to skip:** "tessellation is broken." Check `volume()` on the result + before blaming anything downstream. + +### Fillet silently moves to a different edge after a sketch edit + +- **Symptom:** part looks subtly wrong; no error anywhere +- **Cause:** topological reference resolved by fingerprint below the confidence threshold + and picked the nearest candidate instead of failing +- **Wrong hypothesis to skip:** "the fillet radius is wrong." This is invariant #5 being + violated. Find where the threshold check was skipped. + +### Golden test passes locally, fails in CI + +- **Symptom:** topology hash differs between machines +- **Cause:** `HashMap` iteration order reached the output. Invariant #1. +- **Wrong hypothesis to skip:** "floating point differs between CPUs." It usually does not + at `1e-9` relative for these operations. Check for unordered iteration first. + +### Viewport stutters during recompute + +- **Symptom:** frame drops while a feature rebuilds +- **Cause:** kernel work on the render thread, or a lock held across an `await`/kernel call +- **Wrong hypothesis to skip:** "the GPU is the bottleneck." Profile the frame; it is + almost always a blocked render thread. Invariant #6. + +--- + +## Actual mistakes + +*(empty — add as they happen)* diff --git a/PROJECT_BRIEF.md b/PROJECT_BRIEF.md new file mode 100644 index 0000000..36073e4 --- /dev/null +++ b/PROJECT_BRIEF.md @@ -0,0 +1,211 @@ +# VernierCAD — Project Brief + +> A vernier is the auxiliary scale on a caliper — the mechanism that gets you from +> "about right" to an actual measurement. Also a commune in Geneva, which is a coincidence +> that never needs explaining to anyone. +> +> **Display name:** VernierCAD. The suffix disambiguates from Vernier Software & +> Technology, the US science-education company, and makes the project findable by people +> searching for open-source CAD. +> **Crate prefix, binary, and repo:** plain `vernier`. Nobody wants to type +> `verniercad-occt-sys`. + +A parametric 3D CAD application. Native Linux, GPU-accelerated, history-based modelling +with a B-rep kernel. Fusion 360's model, Shapr3D's restraint. + +--- + +## 1. What this is + +A single-user, solid-modelling CAD app: + +- Sketch on a plane → constrain → extrude/revolve → modify with fillets, shells, patterns +- Full parametric history: edit any upstream feature, everything downstream rebuilds +- Exports STL and STEP; imports STEP +- Runs headless from a CLI for scripting and testing + +**Not** in scope, ever: CAM, simulation, generative design, cloud sync, rendering/animation, +sheet metal, surfacing beyond loft/sweep. Fusion has those. This does not. + +**Not** in scope, for now: assemblies, joints, 2D drawings, multi-body. Phase 8+, if ever. + +## 2. Success metric + +**Parts I have actually made with it.** Not features shipped, not lines written, not +phases completed. The project is working if the count goes up. + +This is the only metric. When a decision is ambiguous, ask which option gets a real part +out of the machine sooner. + +### The ladder + +| Rung | Part | Requires | +|------|------|----------| +| **L0** | Spacer / washer | sketch → extrude → cut → STL | +| **L1** | Bike light mount | constraints, holes, fillets, **edit-after-the-fact** | +| **L2** | Snapmaker jig / enclosure | shell, draft, patterns, naming under stress | +| **L3** | Rod-holder bracket, organic transition | loft, sweep, splines, tangency | +| **L4** | Two-part snap-fit case | multi-body, joints, assembly context | + +**L1 is the real milestone.** Anything can do L0. L1 requires that a sketch edit propagates +through a fillet without exploding — which is the entire problem this project exists to solve. + +### The dogfooding rule + +Once L1 passes, Fusion is only opened for parts Vernier provably cannot express. Every time +it is opened, log the missing feature to `FUSION_LOG.md`. That log is the Phase 5–6 backlog, +ordered by real usage rather than by what is fun to build. + +## 3. Locked decisions + +These were argued out. Do not relitigate without new information. + +| Decision | Choice | Rationale | +|---|---|---| +| **Language** | Rust | Compiler catches what an agent gets wrong. Cargo. wgpu. | +| **Kernel** | OCCT, own `cxx` bridge, behind `trait Kernel` | Booleans, fillets, offsets, STEP on day one. Fornjot spent four years on pure-Rust b-rep and archived in June 2026 with goals unmet. That is the cost of the alternative. | +| **Bridge style** | Thin C++ façade + opaque integer handles | Binding OCCT's `Handle` intrusive refcounting through `cxx` is a months-long fight with no payoff. | +| **No OCAF** | Own the document model | OCAF wants to own document, undo, and persistence. All three are ours. | +| **Sketch solver** | Own, sparse Jacobian + Levenberg–Marquardt | Tractable numerics. Avoids SolveSpace GPLv3. Keeps licence freedom. | +| **Render** | wgpu → Vulkan/RADV | Native. Target GPU is AMD RX 7800 XT, RDNA3, Mesa/RADV. **Never assume NVIDIA.** | +| **UI** | egui, behind an abstraction | Ships fast, wgpu-native. Swap for custom vello later if it reads too "egui". | +| **Interaction model** | Fusion: sketch → history tree | Direct push/pull arrives in Phase 5 *as a timeline feature*, not as a parallel modelling mode. | +| **Units** | Millimetres internally, f64 throughout | | +| **Licence** | GPL-3.0-or-later | Decided 2026-08-07. Strong copyleft: forks and derivatives stay open; proprietary plugins are knowingly off the table. OCCT is LGPL-2.1-with-exception — compatible; link dynamically in dev, statically for release. | + +## 4. The three bets + +Everything else is implementation detail. These three decide whether the project survives. + +### 4.1 The kernel is not the bottleneck + +Fusion feels slow because of recompute strategy, tessellation, and a blocking UI thread. +Shapr3D feels fast because the viewport never drops a frame regardless of what the kernel +is doing. All three of those are ours, not OCCT's. + +**The kernel runs on a worker thread. The render thread is sacred.** A model that takes +eight seconds to recompute must still orbit at monitor refresh while it does. + +OCCT hot paths get replaced later — tessellation first (Phase 7), booleans in 2030, maybe +never. The `trait Kernel` boundary exists so that is possible, not because it is planned. + +### 4.2 Topological naming + +The problem that maimed FreeCAD. Downstream features reference faces and edges of upstream +results. Identify them by ordinal index and a sketch edit silently reassigns a fillet to a +different edge. + +**Identity derives from generative history, never from index, never from pointer.** + +Every kernel operation returns a shape *plus a delta*: + +```rust +pub struct OpResult { + pub shape: ShapeId, + pub modified: HashMap>, + pub generated: HashMap>, + pub deleted: HashSet, +} +``` + +OCCT supplies the raw material: every `BRepBuilderAPI_MakeShape` subclass exposes +`Generated()`, `Modified()`, `IsDeleted()`; boolean operations additionally provide a +`BRepTools_History`. The C++ façade translates those into our stable `EntityId` space via +`TopTools_IndexedMapOfShape`. Rust never sees an OCCT index. + +**Fallback.** When history is unavailable — a sketch edit changed the face count, the +feature re-ran from scratch — match by geometric fingerprint: + +``` +surface type + area + centroid (feature-local coords) + adjacency signature +``` + +Best candidate above a confidence threshold wins. **Below threshold, mark the reference +broken and surface it in the timeline.** Never silently pick the nearest face. Fail closed. + +A wrong-but-plausible face assignment is worse than an error, because the user ships the part. + +### 4.3 Headless-first + +Every modelling operation must be drivable with no window, no GPU, no display, producing a +deterministic artifact that can be asserted on. + +```fish +cargo run -p vernier-cli -- run part.rhai --export out.step --json-report +``` + +This is what makes autonomous iteration possible. A feature that cannot be exercised +headlessly is not finished. + +## 5. Architecture + +``` +crates/ + vernier-occt-sys/ cxx bridge + facade.cpp — the ONLY crate allowed `unsafe` + vernier-kernel/ trait Kernel, OpResult, EntityId; OCCT impl behind it + vernier-solver/ 2D constraint solver. ZERO dependency on kernel. + vernier-doc/ feature DAG, EntityId space, undo stack, serialization + vernier-tess/ tessellation + cache + vernier-render/ wgpu, ID-buffer picking + vernier-ui/ egui shell, viewport widget, timeline + vernier-cli/ headless driver — the agent's entry point + vernier-app/ thin main() +``` + +**Dependency rule:** arrows point downward only. `vernier-solver` and `vernier-doc` must +never depend on `vernier-kernel` or anything below it. That is what keeps them fast to test +and small enough to reason about in one context window. + +### Picking + +Render entity IDs to an offscreen R32Uint target. Read back one pixel. Exact for faces, +edges and vertices, constant time, no raycast geometry. Costs one extra pass; worth it. + +### Build + +OCCT vendored as a git submodule, static link, for reproducibility. A `system-occt` cargo +feature points at the CachyOS package for fast iteration. Keep both — the vendored build +is a coffee break. + +## 6. Phases + +| # | Phase | Effort | Gate | +|---|-------|--------|------| +| **0** | Foundation: wgpu viewport, camera, command bus + undo, doc skeleton, headless CLI, CI | S | `--selftest` passes with no display | +| **1** | OCCT façade, primitives, booleans, tessellation, edge render, ID picking, **STL export**, **naming spec written** | M | Box − cylinder renders; click a face, it highlights | +| **2** | Sketcher + solver: 12 constraints, drag, DOF readout, auto-constraints | **XL** | Fully-constrained sketch does not move when dragged; solver <5 ms @ 200 constraints | +| **3** | Feature DAG, extrude/revolve, incremental recompute, timeline UI, **naming implemented**, save/load, crash recovery | L | **L0** | +| **4** | Hole, fillet, chamfer, shell, draft, patterns, mirror | L | **L1 → switch over** | +| **5** | UX: gizmos, contextual toolbar, snapping, measure, sections, direct push/pull | M | L2 | +| **6** | Loft, sweep, splines, STEP I/O, Rhai scripting | L | L3 | +| **7** | Perf: parallel branch recompute, tess cache, LOD, kernel fully off render thread | M | 500-feature model recomputes with no frame drop | +| **8+** | Multi-body, joints, assemblies, drawings | XL | L4 | + +Rough calibration at ~10 h/week with heavy agent use: L0 around month 4–5, L1 around month 7–9. + +**Phase 2 is where this dies if it dies.** It is a numerical-methods project wearing a UI +costume, and it produces nothing visible until Phase 3 wires it up. Budget for the morale +dip. Consider building the solver's own debug visualiser early — seeing constraint residuals +converge is the only dopamine available in that phase. + +## 7. Risks, honestly + +| Risk | Severity | Mitigation | +|---|---|---| +| Phase 2 morale collapse | **High** | Solver debug viewer. Timebox to 12 weeks. Ship a bad solver and iterate rather than perfecting it dry. | +| Naming design wrong, discovered Phase 4 | **High** | Spec written and reviewed in Phase 1, before `extrude` exists. Adversarial test fixtures from day one. | +| L1 plateau — works, but every real part hits a gap | **High** | `FUSION_LOG.md` discipline. Backlog ordered by real usage. | +| OCCT build friction eats weeks | Medium | `system-occt` feature. Do not fight the vendored build during development. | +| `cxx` + OCCT refcounting rabbit hole | Medium | Opaque handles + C++-side registry. Never expose `Handle` to Rust. | +| Non-determinism makes testing impossible | Medium | Determinism is a hard invariant from Phase 0, not a later fix. | +| egui ceiling on Shapr3D-grade polish | Low | Real, but a Phase 5 problem. UI is behind an abstraction. | +| Scope creep into CAM/simulation | Low | Section 1. Re-read it. | + +## 8. Working agreements + +- Root `CLAUDE.md` holds the invariants. Per-crate `CLAUDE.md` holds local context. +- `MISTAKES.md` at root. Every non-obvious bug that cost more than an hour gets an entry. +- `FUSION_LOG.md` from L1 onward. +- Conventional commits. One logical change per commit. +- No feature merges without a headless test. +- When an invariant in `CLAUDE.md` seems wrong, say so and stop. Do not route around it.