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3dsMax mesh-normals go crazy on skinned-mesh

polycounter lvl 17
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artician polycounter lvl 17
Hey any Max artists in here?

I was hoping someone here had heard of this issue: The normals of my mesh are acting like they're always in local-space when the mesh is skinned and rendered. It seems to make whatever verts that were facing away from the lighting to remain dark, even when the skeletal animation they're skinned to causes them to face a light source.

No change in value. Here are some picks:

Character in the viewport, also with normals exposed:
male_idle_viewport.jpg

A render in the idle pose:
male_idle.jpg

A render (and example of the problem) if I turn his hand palm facing up:
male_badNormals.jpg

This anomaly occurs across all this characters animations (of which there are about 100). It's not occurring on other meshes. The issues goes away if I use Edit Normals modifier to reset the normals, but reappears as soon as the Skin modifier is reapplied. I've exported and reimported the mesh to rid it of any potential meta-data that might be causing it, but it has the same results. Geometry is not doubled up, whole model is in quads, nothing odd is going on here else-wise.

I have found one workaround: I put an Edit Normals modifier on top of the Skin Modifier and played/rendered his animation. This worked for animations that didn't have a great dynamic range, but the same behavior still persisted *except* acted as though the normals were always in the animated position, rather than coming from the neutral/idle pose.

It's definitely an issue with the mesh, not the lighting. I've lit him with several setups and lighting doesn't change the situation.

I'd love to hear folks thoughts on this.

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  • Ace-Angel
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    Ace-Angel polycounter lvl 12
    Which version of Max? Also, what material are you using?

    This is an issue I had with Max 2012+ for viewport shaders, since Max broke them somewhere along the line, but you shouldn't be getting this issue for straight up renders, hmm.
  • artician
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    artician polycounter lvl 17
    Yeah I meant to give that info but wanted to keep the post short-ish and forgot.

    Max2013, Standard material with the only change to it being the Diffuse/Ambient increased to rgb 255,255,255.

    It is quite strange, especially considering it affects the render itself.
  • Noors
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    Noors greentooth
    Never ran across that problem. I dont have 2013 tho.Are you up do date on hotfixes btw ?

    Could it be some option in the skin modifier then ? edit : tested, nothing with such behavior there.
    Did you try to save the skin and reload it on a new skin modifier ?
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