Deformation of model when adding bones

[Artgeek]

Hello everyone,

I am totally inexperienced in 3ds max and I beg for your insight. I created a model which appears to be just fine until I added bones and the skin modifier. Everytime I try to move it, it deforms entirely. Is that a problem with the bones I made, did I use the skin modifier wrong, or is it a problem with the model? I truly do not know what to do and I greatly appreciate any piece of advice or information you can offer.

Thank you very much in advance.

P.S I have attached a picture of the model before I used bones and skin modifier and one after, in case I did not explain it correctly.

[blakestone · Accepted solution]

Before you apply the Skin modifier it is best practice to:

-- Reset Xform : Utilities > Reset Xform

-- Position your Pivot (to where you want...) : Hierarchy > Affect Pivot Only

-- Collapse the Modifier Stack : Utilities > Collapse

Basically this resets the 3D model so that anything you've done prior does not affect the Skin modifier and give results like what you've posted.

If you've done all of the above and the issue still persists then...

The Skin modifier works by assigning a weight value to each of the vertices on your 3D model. When you first apply the Skin modifier and then add the bones, 3dsMax will automatically give each vertice a weight value (in the form of a percentage 0 = 0% and 1.0 = 100%) based on the distance of the closest bone. 99.9% of the time all of these weight values will not be what you want, however it is generally a good starting point. You can also set weight values to multiple bones example.

Vertice: 5 has a weight value of 25% to BoneA and 50% to BoneB and 25% to BoneC... then when you move BoneA Vertice 5 will mode 25%, or if you move BoneB it will move 50% etc. So you can setup blending affects which is great for creases like elbows, knees etc.

If your model is not deforming correctly it is very possible that the weight values need to be configured, this can be a long task depending on the complexity of the model. I suggest starting small example start with one foot and work on these weight values until it deforms correctly, then move onto the next foot etc and work on it piece by piece. A good way to test this is to animte the bones and see how they're deforming, sometimes it may look right but when it's deformed in a particular way it may not be deforming right so it's good to have an animation to see it all moving.

Ben Mathis has a great video demonstrating this here: http://vimeo.com/27211834

[Artgeek]

Oh my God, thank you so much! I knew I had probably bypassed some parts of the procedure but I couldn't find a video sorting it out in its entirety. Thank you very much for your explanations and reference.