Merricksdad's Skin Functions for GMAX/MAX

This is a maxScript tool for Gmax/3dsMAX. Running the script loads up a library of functions and starts a rollout with a few tools for use with Skin Modifiers in Max.

The Tools

The tool rollout comes with the following tools:

1. Set Default Bone: Any vertex without bone weights on the Skin Modifier will be set to the default bone, using the bone name specified
2. Weld Selected: Normally welding verts on the underlying skin destroys the bone and weight information and erases all data for the selected verts. Using this tool allows you to weld the selected verts in the underlying mesh while retaining bone weights. The resulting new vertex will gain the average bone weights of the selected vert.
3. Weld By Threhold: Similar to #2 but welds ALL verts within a threshold. The goal is to weld adjacent verts on the skin to help with smoothing, so the initial threshold is set to 0.1 cm.
4. Report Bad Bone Counts: Will report vertex indices to the Listener Window when a vert uses more than 4 bones
5. Report Bad Weight Totals: Weight totals must equal 100%. Will report vertex indices to the Listener Window when weight totals do not equal 100% +/- 0.006%
6. Select Verts with Bad Bone Counts: As #4 except verts in the underlying mesh are selected. Vertex subobject level is then shown
7. Select Verts With Bad Weight Totals: As $5 except verts in the underlying mesh are selected. Vertex subobject level is then shown
8. Normalize Bone Weights: Vertices with abnormal bone weights are normalized so their total = 100%
9. Reduce Bone Count to Four: Any vertex using more than 4 bones will have the least used bones detached, and then the remaining bone weights will be normalized.

Additional Hidden Functions

If you are fluent with maxScript you can make use of the following functions

1. GetHasSkin()
2. DisableSkinDeform()
3. EnableSkinDeform()
4. SelectSkin()
5. GetBoneNames()
6. GetNumBones()
7. SetupAsBone()
8. GetAllSkinVerts()
9. ExcludeVertsByBone()
10. GetBoneIndex()
11. GetVertBoneWeight()
12. GetNumBonesAffectingVert()
13. GetBonesAffectingVert()
14. GetBoneNamesAffectingVert()
15. GetWeightsAffectingVert()
16. GetBoneWeightPairsAffectingVert()
17. GetBoneWeightArraysAffectingVert()
18. GetAllBoneWeightPairs()
19. GetAllBoneWeightArrays()
20. GetIsVertUsingBoneIndex()
21. GetIsVertUsingBoneName()
22. GetVertsUsingBoneIndex()
23. GetVertsUsingBoneName()
24. SetDefaultBoneIndex()
25. SetDefaultBoneName()
26. ClearWeightsByBoneIndex()
27. ClearWeightsByBoneName()
28. ClearAllBoneWeights()
29. WeldSkinVerts()
30. GetVertsWithinThreshold()
31. WeldSkinVertsByThreshold()
32. GetVertsWithBadBoneCount()
33. ReportVertsWithBadBoneCount()
34. SelectVertsWithBadBoneCount()
35. GetVertsWithUnnormalizedWeights()
36. ReportVertsWithUnnormalizedWeights()
37. SelectVertsWithUnnormalizedWeights()
38. NormalizeWeights()
39. ReduceBoneCountToFour()
40. MoveSkinBoneWeights()
41. SplitBoneWeights()

The above functions using the word "PAIRS" will return inidividual or arrays of structs. The struct layout is as follows:

#Struct:BoneWeight (
  bone:<integer>,
  name:<string>,
  weight:<float>
)

...so the data structure will be used like: <boneweight>[X].name

Above functions that return data as arrays instead of pairs will actually produce one of the above struct, under which bone, name, and weight are actually arrays. You can then access a specific bone name via <boneweight>.name[X]

See the code for notes, including how to use some of the other functions