How to save stl file with color

[ClarkDinh]

Dear Rick van Hattem, I would like to ask you how can I save the stl file with color. I have vertices and faces. I save the mesh in the same way as your description: ---Create the mesh cube = mesh.Mesh(np.zeros(faces.shape[0], dtype=mesh.Mesh.dtype)) for i, f in enumerate(faces): for j in range(3): cube.vectors[i][j] = vertices[f[j],:] --- Write the mesh to file "cube.stl" cube.save('cube.stl')

However, it just saves the grey stl file as the following attachment.

How can I save the stl with color as produced by plot_trisurf.

Thank you very much for your support.

[wolph]

The stl format has no support for color at all. It only consists of a list of triangles and a list of combinations of those triangles to build the structures.

The plot appears to be basing the color on the z height.

[ClarkDinh]

Thanks for your feedback.

[eudoxos]

The stl format has no support for color at all. It only consists of a list of triangles and a list of combinations of those triangles to build the structures.

Binary STL does have limited (RGB) color support, though it is not standardized.

[wolph]

That's an interesting new addition. If there's enough interest I can add it to the library but it looks like it would break most STL software

[eudoxos]

it would break most STL software

No, it uses the 2 attr bytes which are normally unused anyway — you are already reading and writing them, too :

https://github.com/WoLpH/numpy-stl/blob/6f2b6f831f3e372878fb2d19bbfe6c029a2001aa/stl/base.py#L175

[wolph]

I read this and assumed it could be problematic:

in the standard format, this should be zero because most software does not understand anything else.

But you're right, many libraries probably won't care about it.