Shapely polygon from trimesh.path.path.Path2D

I have sliced a 3d mesh with yz planes into several 2d sections (i.e. Path2D objects). Now, I’d like to create Shapely polygons from these 2d sections. For doing so, I need a list of points as XY coords. However, if I use Path2D.vertices, I get a weird polygon because the vertices are un-ordered. Is there any way to get an ordered list of the vertices composing a Path2D object?

Obviously I cannot use the python .sort() method.

[mikedh]

Hey, so what part isn’t working? The polygon is probably displaced if you are using the to_planar method without specifying the matrix.

I updated the section example: https://github.com/mikedh/trimesh/blob/master/examples/section.ipynb check out In[12] to show how to pass the matrix. Also I added In[10] which shows a linestring-polygon intersection.

Best, Mike

[mikedh]

No worries, glad it was a version issue in this case! Though for future people looking at this I actually have another suspect that could possibly touch this too: vertex merging behavior. After a bunch of asks for “no merging by default” my compromise solution was to to consider vertex normals if populated, and only merge vertices that had the same position, vertex normal (if loaded), and UV (if loaded).

For 3D printing-ish stuff, I now load every mesh using loaded = trimesh.load(file_name, merge_norm=True, merge_tex=True). Behavior on STL files (which have no vertex normals) wouldn’t change, but OBJ could.