Rigged mesh has vertex tearing

Hey guys,

We’re in the process of importing our tribal male character as a rigged and animated mesh, and we’re getting some odd issues:

The more he moves in certain directions, the more pronounced the tearing becomes.

At first sight I thought it was something wrong with the weighting - maybe those verts were missed when painting weights - but my (highly qualified) tech animator who rigged and weighted this mesh says the weights are fine.

My second thought was that we had nodes plugged into the world position offset and tesselation inputs for the clothing and the skin - maybe we were doing that wrong - so I unplugged them completely. some of the major tearing went away, but the image I linked is still the current state of the problem.

Any thoughts as to what it could be? I feel like the WPO/tesselation nodes weren’t actually a problem, but they just exacerbated the actual problem.


Usually when this happened to me in UE3 (if you used Maya), I would just click on the trouble mesh, select edit smooth skin > NormalizeWeights. This happened to me in UE4 as well. It should hopefully fix your problem.

What app is the rigging work being done in?

Since I use 3ds Max there is a couple of reasons why this would occur.

More than 4 nods per vertex.

The max number of links, if I recall properly, is 4 in UE4 and since the weights were painted on then there has been more than a few times that I painted excessive links as part of the paint process by accident, this is where weight tables comes in handy, and if more than 4 I’m assuming this would be the result.

Rounding out.

The rounding problem occurs when you have app A set to 3 decimal places and app B set to 2. A single value of .001 is still 100% but when imported into an app set to use 2 it reads the weigh value as .00 which is no weighing at all.

Painting weights is fast but to avoided tearing, in 3ds Max, be sure to set the number of max allowable links to 4 and hit delete zero weights from time to time.

Also as best practice “always” hit you mesh with an exform reset before skinning.

Hope that helps.

We’ve tried the things you guys have mentioned but are still having the same issue. We can’t replicate the problem in Maya.

Are there any known issues regarding the import process for UE4.1 / fbx?

Do you have tessellation enabled on your material for the skeletal mesh?

Removed both tessellation and WPO because we thought that was the problem (as shown in the first post).

I’m sorry - I thought you meant you disconnected the WPO and tessellation multiplier inputs rather than disabling tessellation altogether in the material properties. Only time I saw something similar was with material tessellation set to “PN_Triangles” along the texture seams between some (not all) material elements.

Could you post an image of the problem where we can see the whole character/scene, the origin and the skeleton? I recall having a similar problem in UE3, where I did a cinematic test and animating the skeletal mesh far away from the origin. I essentially mapped the level in unreal and maya 1 to 1 and animated the characters in the exact spot on the map rather than animating near the origin and manually placing the character afterwards. This caused the skin weights to have serious precision issues and the mesh started to look like a hedgehog. I of course changed method and animated near the origin as you’re supposed to.

Another thought is that your technical guy has accidentally gotten some weight to the root joint, if you have one above the pelvis. Usually you don’t notice any problems inside of Maya until you move the character far away from the root joint. This can easily be remedied by either removing the root joint as an influence, the weights should normalize to other influences. You can also select the vertices with the problem and zero out weights for the joint in the component editor.

Actually joe.real the misunderstanding was completely on me! I thought you were referring to disconnecting inputs rather than the setting on the material itself (the one I forgot existed). Turning off tessellation from the dropdown fixed our issue (it was set to PN_Triangles)!

Thanks so much!