updated python exporter from meshio to trimesh (#204)

.github/workflows/manifold.yml

@@ -25,7 +25,7 @@ jobs:
       run: |
         apt-get -y update
         DEBIAN_FRONTEND=noninteractive apt install -y libomp-dev libassimp-dev git libtbb-dev pkg-config libpython3-dev python3 python3-distutils python3-pip lcov
-        pip install meshio[all]
+        pip install trimesh
     - uses: actions/checkout@v3
       with:
         submodules: true

bindings/python/examples/run_all.py

@@ -17,7 +17,7 @@
 import pathlib
 import sys
 import importlib
-import meshio
+import trimesh
 from time import time
 
 if __name__ == "__main__":
@@ -34,8 +34,9 @@
         model = module.run()
         if export_models:
             mesh = model.to_mesh()
-            cells = [("triangle", mesh.tri_verts)]
-            meshio.write_points_cells(f'{f}.ply', mesh.vert_pos, cells)
-            print(f'Exported model to {f}.ply')
+            meshOut = trimesh.Trimesh(
+                vertices=mesh.vert_pos, faces=mesh.tri_verts)
+            trimesh.exchange.export.export_mesh(meshOut, f'{f}.glb', 'glb')
+            print(f'Exported model to {f}.glb')
         t1 = time()
         print(f'Took {(t1-t0)*1000:.1f}ms for {f}')

flake.nix

@@ -26,7 +26,7 @@
               version = "beta";
               src = self;
               patches = [ ./thrust.diff ];
-              nativeBuildInputs = (with pkgs; [ cmake (python39.withPackages(ps: with ps; [meshio])) ]) ++ build-tools ++
+              nativeBuildInputs = (with pkgs; [ cmake (python39.withPackages(ps: with ps; [trimesh])) ]) ++ build-tools ++
                 (if cuda-support then with pkgs.cudaPackages; [ cuda_nvcc cuda_cudart cuda_cccl pkgs.addOpenGLRunpath ] else [ ]);
               cmakeFlags = [
                 "-DMANIFOLD_PAR=${pkgs.lib.strings.toUpper parallel-backend}"