Hey folks!

I've been working on a Rust crate called Anvil that aims to make 3D CAD modeling intuitive and reliable. It's early-stage and built on top of opencascade-sys, but we've added a lot of structure and consistency to the modeling workflow.

What is Anvil?

Anvil is a 3D and 2D modeling crate focused on:

• Consistent APIs: Similar interfaces between 2D and 3D operations (e.g., add, subtract, intersect)
• Mandatory units: All lengths and angles require explicit units (e.g., length!(16 mm)), avoiding hidden assumptions
• Tested by design: Almost all public APIs are tested, ensuring correctness and maintainability

Example: Making a LEGO brick in code

Here’s how you’d build a simple 2x2 LEGO-style block:

let block_width = length!(16 mm);
let block_height = length!(9.6 mm);
let stud_height = length!(11.2 mm) - block_height;
let stud_distance = length!(8 mm);
let stud_diameter = length!(4.8 mm);

let block = Cuboid::from_dim(block_width, block_width, block_height);

let studs = Cylinder::from_diameter(stud_diameter, stud_height)
    .move_to(Point3D::new(
        stud_distance / 2.,
        stud_distance / 2.,
        (block_height + stud_height) / 2.,
    ))
    .circular_pattern(Axis::z(), 4);

let part = block.add(&studs);
// see full example and result in the README

Why Anvil?

We initially used opencascade-rs for another project but ran into a few blockers:

• Missing basic traits like Clone or PartialEq
• Lack of documentation and tests
• Inconsistent and unintuitive APIs

So we built Anvil on top of opencascade-sys, wrapping it with a safer, more ergonomic Rust interface.

Would love feedback on

• API design: Is it idiomatic? Any major smells?
• Missing features you would expect in CAD modeling?
• Anyone interested in contributing or collaborating on a custom kernel down the road?

-> Check out the Github repo for more information

Thanks for reading — and happy modeling!