[V-HACD] Adaptive Convex-Hulls Sub-sampling

Today, I took some time to add a new parameter (i.e., minVolumePerCH) to V-HACD to adaptively control the number of vertices/triangles of the generated convex-hulls. Below some results for different values of minVolumePerCH.

Who is using V-HACD?

Please, let me know if you are using V-HACD in your products

• Leadwerks
• 3DEXCITE
• Unreal Engine 4
• DBPro
• HighFidelity
• Bonzai Engine

V-HACD Blender Add-on (by Alain Ducharme)

Checkout this Blender add-on released by Alain Ducharme!

V-HACD 2.0 Parameters Description

Parameter name	Description	Default value	Range
resolution	maximum number of voxels generated during the voxelization stage	100,000	10,000-64,000,000
depth	maximum number of clipping stages. During each split stage, all the model parts (with a concavity higher than the user defined threshold) are clipped according the "best" clipping plane	20	1-32
concavity	maximum concavity	0.0025	0.0-1.0
planeDownsampling	controls the granularity of the search for the "best" clipping plane	4	1-16
convexhullDownsampling	controls the precision of the convex-hull generation process during the clipping plane selection stage	4	1-16
alpha	controls the bias toward clipping along symmetry planes	0.05	0.0-1.0
beta	controls the bias toward clipping along revolution axes	0.05	0.0-1.0
gamma	maximum allowed concavity during the merge stage	0.00125	0.0-1.0
pca	enable/disable normalizing the mesh before applying the convex decomposition	0	0-1
mode	0: voxel-based approximate convex decomposition, 1: tetrahedron-based approximate convex decomposition	0	0-1
maxNumVerticesPerCH	controls the maximum number of triangles per convex-hull	64	4-1024
minVolumePerCH	controls the adaptive sampling of the generated convex-hulls	0.0001	0.0-0.01

V-HACD 2.0 vs. HACD

Below some approximate convex decomposition results comparing V-HACD 2.0 and HACD.

Parameters:

• testVHACD.exe %%i 8000000 20 0.003 4 4 0.05 0.05 0.0015 0 0 256 0.0 %%i.wrl log_%%i.txt
• testHACD.exe %%i  2 50 0 0 1 30 2000

Score:

• +1: V-HACD provides better decomposition than HACD
• -1: HACD provides better decomposition than V-HACD
• 0: V-HACD and HACD provide comparable results

V-HACD 2.0	HACD	Score
18 convex-hulls	66 convex-hulls	1
18 convex-hulls	26 convex-hulls	1
16 convex-hulls	12 convex-hulls	-1
30 convex-hulls	28 convex-hulls	0
46 convex-hulls	54 convex-hulls	1
18 convex-hulls	26 convex-hulls	1
16 convex-hulls	19 convex-hulls	0
18 convex-hulls	22 convex-hulls	0
34 convex-hulls	17 convex-hulls	1
18 convex-hulls	13 convex-hulls	-1
25 convex-hulls	28 convex-hulls	1
20 convex-hulls	15 convex-hulls	-1
22 convex-hulls	16 convex-hulls	-1
42 convex-hulls	42 convex-hulls	0
9 convex-hulls	7 convex-hulls	-1
16 convex-hulls	15 convex-hulls	1
35 convex-hulls	37 convex-hulls	0
17 convex-hulls	17 convex-hulls	0
18 convex-hulls	18 convex-hulls	0
36 convex-hulls	34 convex-hulls	0
13 convex-hulls	10 convex-hulls	-1
11 convex-hulls	5 convex-hulls	-1
24 convex-hulls	20 convex-hulls	1
35 convex-hulls	36 convex-hulls	0
21 convex-hulls	13 convex-hulls	-1
15 convex-hulls	16 convex-hulls	0
9 convex-hulls	10 convex-hulls	0
41 convex-hulls	71 convex-hulls	0
22 convex-hulls	27 convex-hulls	0
47 convex-hulls	51 convex-hulls	0
23 convex-hulls	28 convex-hulls	0