Added sketch origin and sketch 3d printing functionality

[Gip-Gip]

An origin is now stored in a private field in sketches that allows the end user to place and extrude sketches at any coordinate in 3d space. Along with the origin is another private field which stores the transform data that is needed to transform each point when meshing.

High-level PR Summary

This PR adds the ability to position and orient 2D sketches in 3D space before extrusion by introducing an origin field (stored as a Vertex) to both Sketch and Mesh structures. The implementation includes transformation logic using quaternions to rotate sketch geometry according to the origin's normal vector, along with a new build_graphic_line_strings method for 3D visualization of sketch edges. The origin and its pre-computed transformation data are propagated through all sketch and mesh operations including CSG operations, extrusions, and conversions.

⏱️ Estimated Review Time: 30-90 minutes

💡 Review Order Suggestion

Order	File Path
1	src/mesh/vertex.rs
2	src/sketch/mod.rs
3	src/sketch/shapes.rs
4	src/sketch/hershey.rs
5	src/sketch/extrudes.rs
6	src/mesh/mod.rs
7	src/mesh/flatten_slice.rs
8	src/sketch/offset.rs

[gemini-code-assist]

Summary of Changes

Hello @Gip-Gip, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the geometric modeling capabilities by introducing a robust 3D origin and transformation system for Sketch objects. It enables users to define 2D sketches at arbitrary positions and orientations in 3D space, and then seamlessly extrude or convert them into 3D meshes that accurately reflect their intended spatial placement. Furthermore, it provides new utilities for generating 3D graphic line representations of sketches, which are invaluable for visualization and integration into 3D printing workflows.

Highlights

• Sketch Origin and 3D Placement: The Sketch struct now includes an origin field (a Vertex) and an origin_transform to define its position and orientation in 3D space. This allows 2D sketches to be placed and manipulated anywhere in a 3D environment before being converted to meshes.
• Integrated 3D Transformation: New macros (apply_origin_transform!, apply_origin_transform_graphicpoint!) and a helper function (prepare_origin_vec_and_quat) have been added to apply the sketch's origin transformation to its geometry, ensuring that extruded meshes and graphic representations are correctly positioned and oriented in 3D.
• 3D Graphic Line Generation: A new build_graphic_line_strings method allows generating 3D line representations of sketches, respecting their defined origin. This functionality is crucial for visualization, debugging, or exporting data for 3D printing applications.
• Mesh Origin Propagation: The Mesh struct has been updated to also store an origin, ensuring that 3D meshes created from sketches or other operations retain their spatial context and can be consistently transformed.

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[recurseml]

Review by RecurseML

🔍 Review performed on 278e025..acff835

✨ No bugs found, your code is sparkling clean

✅ Files analyzed, no issues (7)

• src/mesh/flatten_slice.rs
• src/mesh/mod.rs
• src/mesh/vertex.rs
• src/sketch/extrudes.rs
• src/sketch/hershey.rs
• src/sketch/offset.rs
• src/sketch/shapes.rs

[gemini-code-assist]

Code Review

This pull request introduces an origin to sketches and meshes, allowing them to be positioned and oriented in 3D space. The changes are extensive, touching CSG operations, extrusions, and conversions to propagate this new origin information. My review found a few issues. There are critical bugs in the new transformation macros that would lead to incorrect geometry when a 180-degree rotation is needed. Additionally, the revolve function has been partially updated but is missing the application of the origin transform to its generated geometry, making it inconsistent with other extrusion functions. I've provided detailed comments and suggestions for these issues.

[gemini-code-assist]

There's a bug in the apply_origin_transform! macro when two quaternions are used for rotation. The second rotation quat2 is applied to the original vertex position and normal ($in_vertex), overwriting the result of the first rotation (quat1). It should be applied to the already-rotated out_vertex to compose the rotations correctly.

Suggested change

	out_vertex.pos.coords = quat2 * $in_vertex.pos.coords;
	out_vertex.normal = quat2 * $in_vertex.normal;
	out_vertex.pos.coords = quat2 * out_vertex.pos.coords;
	out_vertex.normal = quat2 * out_vertex.normal;

[gemini-code-assist]

Similar to the apply_origin_transform! macro, there's a bug here. The second rotation quat2 is applied to the original point coordinates ($in_point.coords), overwriting the result of the first rotation. It should be applied to the already-rotated out_point.coords.

Suggested change

	out_point.coords = quat2 * $in_point.coords;
	out_point.coords = quat2 * out_point.coords;

[gemini-code-assist]

The origin field is now correctly propagated to the Mesh created by revolve. However, the origin_transform is not being applied to the vertices of the revolved geometry. This means the resulting mesh will be located at the world origin, not at the sketch's origin, which is inconsistent with extrude_vector.

To fix this, self.origin_transform should be passed down to the revolve_ring and build_cap_polygon helper functions. Then, the apply_origin_transform! macro should be used on each created Vertex, similar to how it's done in extrude_geometry.

[Gip-Gip]

Fixed the quat bugs, I'm going to need to look further into the revolve function though it looks like it will have to take more finesse.