szabolcsdombi/python-mesh-raycast

python-mesh-raycast

Ray-casting on meshes for python.

Install

This module is not available through pip, it was designed to be forked and extended. Simplicity is a key goal in design. This module is using glm and the Python's c-api. The implementation can be found in the mesh_raycast.cpp.

git clone https://github.com/cprogrammer1994/python-mesh-raycast
cd python-mesh-raycast
python setup.py develop

Cheat Sheet

import mesh_raycast

triangles = np.array([
    [0.0, 0.0, 0.0],
    [4.0, 0.0, 0.0],
    [0.0, 4.0, 0.0],
], dtype='f4')

result = mesh_raycast.raycast(source=(0.4, 0.8, 5.0), direction=(0.0, 0.0, -1.0), mesh=triangles)

The result is a list of objects with the following keys:

{
    'face': 0,
    'point': (0.4, 0.8, 0.0),
    'normal': (0.0, 0.0, 1.0),
    'coeff': (0.1, 0.2),
    'distance': 5.0,
    'dot': 1.0,
}

• face is the index of the triangle from mesh
• point is the point in world coordinates where the ray and the triangle intersects
• normal is the normal of the triangle
• coeff is a pair of coefficients from the internal calculations
• distance is the distance between point and source
• dot is the dot product of -direction and normal

sorting the result

sorted(result, key=lambda x: x['distance'])

filtering the result

first_matching_face = min(result, key=lambda x: x['distance'])['face']

non_backfacing = filter(lambda x: x['dot'] > 0.0, result)