Mesh flip problem with Skin in 3ds Max

splinter

I'm using the Skin modifier and it is working fine except for one part. The vertices from the neck seem to flip the mesh in 180 degrees when I rotate the model backwards (even with the smallest angle possible). The strange thing is that it doesn't happen when I rotate forward. Anyone know what can it be?

Thanks in advance!

Bad Spleen

Is this a custom rig? If so it's to do with the bones rotation, not the skinning. As you rotate it beyond vertical, it is essentially spinning 180 to compensate. I think it may be to do with gimbal lock.

This video may help, but without having the scene in front of me it could be difficult to diagnose.

[ame="http://www.youtube.com/watch?v=zc8b2Jo7mno"]Euler (gimbal lock) Explained - YouTube[/ame]

gHys

to fix gimbal lock choose different axis order from xyz to like zxy or so and see if it's enough. if not make another gruop as father and rotate it. it'll give you 90° more of rotation before gimbal lock if you choose the wrong axis

monster

Are you using a LookAt constraint on the neck? If so you need to set the up node to prevent flipping.
I don't think this is a gimbal lock issue. That mostly has to do with animation and not just a single pose.

splinter

Thank you all for the answers! I think the problem was really with the LookAt constraint. I made some changes on the nodes and now it's working fine.

:thumbup: