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Grasshopper Visualization

This tutorial explains how to visualize COMPAS Slicer results in Rhino/Grasshopper.

Important

The Grasshopper components only visualize existing results. All slicing computation happens in Python - the components load and display the JSON output files.

Setup

  1. Install COMPAS Slicer (see Installation)

  2. Install Grasshopper components:

    python -m compas_rhino.install -v 8.0

Workflow

graph LR
    A[Python Script] -->|generates| B[JSON Files]
    B -->|loaded by| C[GH Components]
    C -->|displays| D[Rhino Geometry]
  1. Run your Python slicing script
  2. Output files are saved to project/data/output/
  3. Open the Grasshopper file in project/
  4. Click Recompute on components to load latest results

Project Structure

my_project/
├── data/
│   ├── model.obj           # Input mesh
│   └── output/
│       ├── slicer_data.json
│       └── out_printpoints.json
├── my_script.py            # Python slicing code
└── visualization.gh        # Grasshopper file

Tip

Place your .gh file in the project root folder so components can find the data/output/ folder.

Components

csLoadSlicer

Loads slicer results from JSON, including all layer and path data.

Slicer component

Outputs:

  • Layers (list of paths per layer)
  • Path geometry (polylines)
  • Layer heights

csLoadPrintpoints

Loads the printpoints dictionary with all fabrication parameters.

Printpoints component

Outputs:

  • Point locations
  • Velocities
  • Extruder states
  • Up vectors

csLightPathViz

Creates a lightweight visualization of toolpaths.

Lightweight visualization

  • White tubes: Print paths
  • Orange tubes: Travel moves

csRenderPathViz

Creates a detailed visualization with actual path cross-sections.

Render visualization

Requires a cross-section curve as input for accurate representation.

Example Workflow

  1. Run Python script:

    from compas_slicer.slicers import PlanarSlicer
from compas_slicer.utilities import save_to_json

slicer = PlanarSlicer(mesh, layer_height=2.0)
slicer.slice_model()
save_to_json(slicer.to_data(), OUTPUT_PATH, 'slicer_data.json')

  2. In Grasshopper:

    • Add csLoadSlicer component
    • Connect to visualization components
    • Click Recompute after each Python run