I did a variety of tests when it came to tessellation using PN Triangles with 2 materials on one model. There are no issues if I’m using a static mesh. As soon as I bring in a skinned mesh, one of the materials extends the tessellation past the UV island.
The example in my post shows a static mesh on the left, with one tessellated material applied to the problem UV island. That tessellates fine. If I apply the same material to the lower half they both tessellate correctly.
The right is a skinned mesh. As you can see the tessellation extends beyond where it should. I thought it could be a skinning issue, so I made sure the area where the second material is applied had a weight of 100% to the head bone. So that doesn’t seem to be the problem.
If I switch from PN Triangles to Flat Tessellation, both halves tessellate correctly. Do you have any thoughts as to what else I can try, or is this a bug that needs to be looked at? I’d like to use one continuous mesh if possible.
Just so you’re aware. I am currently looking into this issue. I have another issue that is similar I’ve been going over as well. I’ll be able to look at this more over the next few days hopefully.
We have a good support staff but also a lot of issues we are assigned and must look into as well. Thank you for your patience.
I’ve been trying to replicate your issue with a simple asset I’ve made but cannot get the same results.
I am currently testing with 4.5.1.
I created a sphere with a two bones and assigned two materials similar to your character head. I’ve setup both materials to use tessellation. I tested with PN and FLAT with no issue.
Are you able to reproduce this on a simple asset or anything other than your skeletal mesh? I would like to narrow down if this is a issue with the skeletal mesh or possibly a bug.
I couldn’t get the same problem when I added bones to a cylinder. It could be an issue with the way the rig is generated using ART. Were you able to test a rigged character using that? I just rigged another character today using ART, and I get the same problem. I’m using a fresh project with 4.5.1, a new material, and a newly imported character.
Well I tried a new character mesh and my current ART skeleton setup. That seemed to work fine.
I also tried to take my problem mesh, re-skin it, and that still has the problem.
I also re-organized the UVs and that didn’t help.
I also tried to take my character mesh and separate the head from the body, giving me two objects. I skinned those, and that still gave me the problem as well.
I’m not sure what else to try… Could it be a normal issue?
It turns out the my mesh had some issues that weren’t visible. I deleted the faces where the seam of the two materials were, rebuilt that, and now it works. Thanks for your help Tim.
Great! Glad this worked out! Apologies for the long wait on this one. If you are still having issues I can feel free to let me know and I’ll look into it.
It turns out that wasn’t the problem. If I take the same model; one with skinning applied and the other without, export them out with FBX into U4, the non-skinned mesh works fine and the skinned one has the “spikes”.
I’m using one material with two instances of it. Both instances have the same parameters, but just a diffuse color change. If I assign both those instanced materials to the polygons that have the 2nd material applied in Maya, the “spikes” go in a different direction.
Could it be that the way I’m creating my second material in Maya is the problem? What I do is import my mesh which already has the default “Lambert1” material applied, select the polygons that I would like to assign a new material to, right-click and choose “Assign a New Material…” Then I export that as an FBX. Within the FBX settings I only have “Smoothing Groups” and “Reference Assets Content” selected under the Geometry dropdown.
Maybe it could be an FBX exporting problem too? Anything else I should check off?
I added a screenshot to the URL above if that helps.
Nevermind Tim. I exported a test model created in Softimage and it worked fine. I have no idea why my original mesh is having issues. I might have to rebuild it, unless you know of a way that Maya can detect any problems
It seems to be some sort of skinning issue. The character tessellates fine without skinning, but as soon as I do that it has issues; both with using ART,and a custom skeleton build using the joint tools in Maya.
I’m not exactly sure why this is happening. I’ve not used Maya before very much so I’m not familiar with a way to check off han. I’ve only got access to 3Ds Max directly for my testing on my system. If the problem keeps happening with your mesh specifically we can dig deeper into this.
I updated my forum post: Click Here. I re-built my mesh and skinned it in Maya, and I get the same results once again. If you’d like I can send you my mesh and if you have time you can see if it creates issues on your end.
Here is another test mesh, this time a basic model with a custom skeleton created in Maya with the join tools. I also included a non-rigged mesh. If you import them both into U4 and assign a tessellated material into the channels, the non-rigged mesh tessellates correctly and the rigged one has the spiking issues.
I also posted in your Forum post, but it looks like the issue is in your weighting of certain verts in the head. Your new test assets do not spike at all when I import them.
Your original assets can be fixed by correcting this weighting issue on both the left and right Thigh_Twist:
Are you sure you’re setting your tessellation to PN triangles? Screenshots are in my thread, along with a better description and my final models results and weighting.
