Vertex Weights Problem

[Delta4907]

Does anybody know why this happens:
http://i308.photobucket.com/albums/kk356/DELTA-49/AHOBOV12009-06-2900-27-37-61.png

It appears fine and moves correctly in 3ds Max, but when I go to test it in Sapien, the vertex weights are all screwed up. This happens on other areas of the model, but at this spot it seems to be the worst. I've tried convert-to-mesh and re-rigging it, but that doesn't seem to change anything. The biped is using stock marine animations, if anyone is curious. I'm using JMS Exporter V2.

[Matooba]

Looks like the vertices between the bones are not bias weighted to 1.
The vertices at the joints between bones should equal 1.
ie...forearm @ elbow 0.5 to upper arm @ elbow 0.5 = 1
Also make sure your vertices are attached to the proper envelopes.

When I assign vertex weights manually, I do the following:

1. Select a bone from the Bones list in the Skin modifier. Any vertices that are weighted to the currently selected bone will have color (blue = low weight / red = high weight). You might want to do this in wireframe mode - I have had some display issues in max 2009 in shaded mode.

2. Select any vertices that you wish to weight and then type in the desired weight in the Abs. Effect parameter and then press Enter. If you want to remove vertex weight completely, enter 0 as the Abs. Effect weight.

Note: When checked, the Normalize option forces the total weights (from all the bones it is assigned to) of each selected vertex to add up to 1. So, if a vertex is weighted .4 to bone 1 and .6 to bone 2 - if you set the bone 1 weight to 0, the bone 2 weight will automatically change to a weight of 1.0.

There are many other ways to assign weights manually such as painting weights or using the weight table to change vertex weights in a spreadsheet fashion.

To sum up, if you select a bone from the Bones list and you see colored vertices that means you have vertices weighted to that specific bone. You should then be able to move that bone in the viewport and watch those weighted vertices follow.

Also:

1. Make sure your Skin modifier isn't turned off (lightbulb icon in modifier stack - white = on, gray = off).

2. Make sure your Edit Poly modifier/object below the Skin modifier has not been left in sub-object mode. If so, the skin modifier will only affect the selected sub-objects (if any are selected).

3. If your vertices don't change color based on the size of your envelopes, the vertices are probably also weighted to another bone and the Abs. Effect setting is preventing them from being influenced further.

4. Try opening the Weight Table and changing the drop-down list value to "Selected vertices". Then select vertices in the viewport and those vertices will be shown in the Weight Table. You will then be able to tell which bones the vertices are weighted to.


Theres some good tuts out there on weighting your vertices. Look around.

Quick Overview:
The bulk of the work in skins is adjusting the size and overlap of all the envelopes to fine-tune mesh behavior as the character moves. Each area of the mesh requires some thought.


The head should have little deformation, so assign it a rigid envelope.
The three pelvis envelopes must be adjusted for proper deformation.
The arm and shoulder envelopes must cover the armpits.

As you adjust the envelopes, scrub the time slider and rotate a User viewport. Moving a character reveals different flaws in the mesh as the biped posture changes in the animation.
Tip: While adjusting envelopes, you can use In Place mode on the Motion panel General rollout. In Place mode keeps the character in a viewport limiting center of mass motion about the XY axes.
After attaching the mesh to the biped with skin modifier, parts of the mesh may stretch off the body. Vertices that are not within envelopes remain in their original positions and create stretched polygons. Roughly adjust the radial scale of the envelopes to pull in these vertices and then begin the process of fine-tuning the envelopes. For example, vertices on the mesh fingers may not be covered by envelopes creating the stretched polygons when animation is loaded.



You can find more tips here (http://www.webreference.com/3d/lesson99/)
Turbosquid free video tut on skin modifier here (http://www.turbosquid.com/FullPreview/Index.cfm/ID/269783)
I hope this is helpful.

[Delta4907]

The thing is, I've rigged it and it appears fine in 3ds, I even imported animations to check, all the vertexes move fine, but after exporting and running through tool, some vertexes appear to be weighted to the wrong bone or something. I've double checked and all the vertexes equal 1 according to their Abs. Effect.

[Roostervier]

Is the bone affect limit set to 2? If it's set any higher, you're going to have problems.

[Delta4907]

Oh, can't believe I forgot about that. Thanks it worked. :)

[malolo420]

Is that delta from DMT? I'm coming back to finish overdose. Gunna install xfire again soon.
Buddys gunna upgrade my comp to a GB graphics card, at least another GB of ram, a TB hard drive and a surround sound sound card.

[Delta4907]

Oh hey malolo! Yeah it's me Delta, you need to get xfire soon.. Lol.

[Inferno]

Is that delta from DMT? I'm coming back to finish overdose. Gunna install xfire again soon.
Buddys gunna upgrade my comp to a GB graphics card, at least another GB of ram, a TB hard drive and a surround sound sound card.

That'll be a sick rig man. We HAVE to play cod4 PC together sometime.