Infinite loop when initializing bones about dem-bones HOT 4 CLOSED

Hi Chad,
Sorry for the late reply.
I have looked thru the dataset you sent and found that the initialization does not work when the model is dominated by static (non-deformed) geometry. In this case, the back of the head and back of the neck (non-deformed) are relatively larger than the frontal parts (deformed). The [cluster splitting] will fail:

There are some practical fixes you could do:

• Removing the static geometries from the data, e.g. the back of the head.
• Changing the distance function for cluster splitting: change this line to double tmp=e*(u.col(i)-cu.col(j)).norm();. The original function is reported in Equation 1 of Robust and Accurate Skeletal Rigging from Mesh Sequences. But this is a "hacky" solution.

from dem-bones.

Hi,
I have encountered an infinite loop myself on a cloth simulated sphere model. (files attached). It works with nBones=30 and below but runs into an infinite loop on nBones=40.

1 animated mesh sequence(s):
    "ballAnim.abc" + "ball.fbx" --> "Decomposition_40.fbx"
Parameters:
    nBones (target)    = 40
    nInitIters         = 10 (default)
    nIters             = 30 (default)
    nTransIters        = 5 (default)
    nWeightsIters      = 3 (default)
    bindUpdate         = 0 (no update) (default)
    transAffine        = 10 (default)
    transAffineNorm    = 4 (default)
    nnz                = 8 (default)
    weightsSmooth      = 0.0001 (default)
    weightsSmoothStep  = 1 (default)
Checking ABCs:
    "ballAnim.abc": /pSphere1/outputCloth1 (313 frames)
Reading ABCs.................................................... Done!
Reading FBXs:
    "ball.fbx"... Done!
    382 vertices
Initializing bones: 1>2>4>8>15>20>23>26>28>29>29>29>29>29>29>29>29>29>29>29>29>29>29>

decompData.zip

from dem-bones.

Hi Max,

The bones initialization will try to allocate at least nnz vertices per bone. Bones with less than nnz vertices will be removed (here).

In your case, the initialization stopped at [nBones=29] * [nnz=8] = 232/382 vertices when the initialization cannot insert more bones in the gaps between vertices.

You can fix it either by:

• Reducing nnz,
• Or modifying the code to, e.g. pruneBones(4).

However, the result will be impractical because skinning will use almost the same amount of data as alembic cache.

from dem-bones.

Fixed in v1.1.0

from dem-bones.