Assignment 01: Brep Mesher + Reciprocal Frame

Goal: build a UV-based mesher for a Rhino Brep and use the resulting mesh as the topology for a reciprocal-frame structure materialized with COMPAS Timber.

Your starting point is a01_brep-mesher.ghx. It includes a scaffold and in-place guidance comments. This line-by-line guidance can be ignored if desired to implement in a different way.

Learning Goals

By the end of this assignment, you should be able to:

• Sample a Brep surface in UV space.
• Build a compas.datastructures.Mesh from sampled points.
• Filter mesh faces against a trimmed Brep boundary.
• Store custom attributes on mesh edges (centerline, normal, next_edge, prev_edge).
• Convert abstract geometry (lines) into timber elements (Beam) and joint logic (JointRules).

Assignment Overview

The assignment is split into three layers in three separate Python files:

1. Meshing (a01_mesher.py)
   • Build a mesh from a single-face Brep.
   • Start with the quad mesher.
   • Optionally extend to other topologies.
2. RF logic (a01_rf_system.py)
   • Use mesh edges as reciprocal-frame beams.
   • Compute edge-to-edge relationships and editable centerlines.
3. Timber model (a01_timber_model.py)
   • Following up on A00, this version of TimberModelCreator is designed to work with the RF system instead of just lines.
   • Turn RF centerlines into beams.
   • Apply joint rules and process joinery.

Main Task

• Create a QuadMesher class:
  • The class should take a Rhino Brep as input and generate a compas.datastructures.Mesh.
  • Focus on creating a Quad Mesh that follows the surface’s UV logic.
• Integrate the mesh into the RFSystem:
  • Use the mesh faces to define the centerlines of a reciprocal frame.
  • Ensure that each edge carries the necessary attributes: centerline, normal, and connectivity (next_edge, prev_edge).
• Materialize with compas_timber:
  • Implement the TimberModel logic to convert the RF system into a 3D timber structure.
  • Use appropriate JointRules or direct joint assignments for XLapJoint, TButtJoint, and LMiterJoint (or explore other joint types available in the compas_timber library).
• Topics: Brep geometry, Mesh datastructures, Reciprocal Frames, COMPAS Timber Model.

Challenge 01

• Vertex-On-Face: Implement a method to check if a generated mesh vertex actually lies on the Brep’s face to allow for trimmed surfaces or surfaces with holes.
• Topics: Geometry (Point in surface, Closest point), Brep topology.

Challenge 02

• Alternative Topologies: Add TriMesher and/or HexaMesher class implementations.
• Reuse as much logic as possible (sampling, filtering, cleanup).
• Test whether your RF logic still works with different valencies.
• Topics: Mesh subdivision, Dual meshes, Hexagonal grids.

Deliverables

Submit the following files:

• Grasshopper File (.ghx)
  • File Name: mustermann_max_A-01.ghx
• All python files (.py):
  • a01_mesher.py
  • a01_rf_system.py
  • a01_timber_model.py
• Screenshots (.png)
  • File Name: mustermann_max_A-01_xx.png
  • Dimensions: 3200 x 2400 px
  • View: Parallel, Shaded

Submission

Upload the assignment via POLY.GRADE