The number of faces is 4x larger compared to vhacd in a test model

[fy0]

out.glb is coacd result, 25 piceces, 1254 triangles

code:

import coacd
import trimesh
import numpy as np

input_file = './input.obj'
mesh = trimesh.load(input_file, force="mesh")
mesh = coacd.Mesh(mesh.vertices, mesh.faces)

parts = coacd.run_coacd(mesh, merge=True, threshold=0.05, resolution=2000, preprocess_resolution=50) # a list of convex hulls.

mesh_parts = []
for vs, fs in parts:
    mesh_parts.append(trimesh.Trimesh(vs, fs))

scene = trimesh.Scene()
np.random.seed(0)
for p in mesh_parts:
    p.visual.vertex_colors[:, :3] = (np.random.rand(3) * 255).astype(np.uint8)
    scene.add_geometry(p)

scene.export('./out.glb')

out2.glb is vhacd, 27 piceces, 374 triangles

code:

import trimesh
import numpy as np

input_file = './input.obj'
mesh = trimesh.load(input_file, force="mesh")

parts = trimesh.interfaces.vhacd.convex_decomposition(mesh, maxhulls=10)

#print(parts)

#mesh_parts = []
#for vs, fs in parts:
#    mesh_parts.append(trimesh.Trimesh(vs, fs))

scene = trimesh.Scene()
np.random.seed(0)
for p in parts:
    p.visual.vertex_colors[:, :3] = (np.random.rand(3) * 255).astype(np.uint8)
    scene.add_geometry(p)

scene.export('./out2.glb')

source model:

files:
test.zip

I feel like the triangles are mainly on the smooth edges. Is there a way to make the edges of the model sharper?

P.S. windows verison seems not work, tested on 2 computers, windows11 anaconda python 3.10.

[Lootheo]

I have this same issue, is there a way to not generate those smooth edges?

Also I cant seem to be able compile on windows.

[SarahWeiii]

The smooth edge problem is caused by mesh pre-processing, which turns a non-manifold mesh into manifold one, and it can introduce more triangles and smoothen the edges.
You may disable the pre-process by adding preprocess=False to run_coacd and then the algorithm will keep the original shape as much as possible. Though using non-manifold mesh as input may have the risk of breaking the algorithm, it works in most cases in practice.

This is the result disabling pre-process with default parameters. (python py_example.py -i input.obj -o coacd_out.obj --no-preprocess)
[17 pieces / 145 vertices / 222 faces]

coacd_out.zip

For the windows compiling problem, make sure you are using the latest code (we have updated it for windows a few weeks ago), and you may try installing vc redist.