In recent days we exported a mesh from Maya 2015 using XMesh MY 1.3.3.58679. When we are loading the XMesh cache into 3ds Max 2015 with XMesh MX Loader 1.3.3.58467 the smoothing groups are wrong. Please see the attached screenshot.
You’ll find the XMesh cache in the attached ZIP-package. I know the topology is not the best, but I couldn’t find any reason why this shouldn’t transfer properly. There are no duplicate vertices and the hard edges are all set correctly. I tried to rebuild the same topology, but it would always transfer properly.
Can you see why this XMesh cache wouldn’t create correct smoothing groups in 3ds Max? Since the mesh looks correct in Maya it’s impossible for us to catch this error before loading the XMesh cache in 3ds Max. Any help is greatly appreciated.
Thank you for your report! I think I’ll need to take a look at the original object in Maya to figure out what’s going on here. Would it be possible for you to please send us a copy of your Maya scene file? You can send us files by using our ticket system. You may need to ZIP your scene file to get it through.
Thank you for your quick response. I just opened a ticket in your system where I attached a Maya scene with the original object. The ZIP package also contains another XMesh cache and a screenshot where I circled the problematic areas.
Please let me know if you need any further information.
It looks like we don’t properly handle the case where a vertex is connected to more than three hard edges. In your case, there are four hard edges connected to the vertex that you circled. The face with a visibly bad normal (outlined below in blue), and the face that’s kitty-corner to it (hidden, outlined in red), were both assigned the same smoothing group, but they should be different.
Thank you for looking into this. It doesn’t fail in all cases. I rebuilt a mesh with the same topology (one vertex and four hard edges) in different ways from scratch and in all cases Xmesh handled them like expected. That makes me wondering what’s wrong with the mesh I sent you.
The bug is pretty annoying since there is no indication of the problem till you load the mesh into 3ds Max. I’m not aware of any other mesh with this issue right now, but in the next weeks and months we will move a lot of assets from Maya to 3ds Max.
When you’re trying to reproduce the problem, one complication is that you need more than one face connected by a soft edge to trigger the creation of a smoothing group. If a face isn’t connected to another face by a soft edge, then it’s assigned smoothing group 0 (i.e, no smoothing), and it avoids this problem.
So, for example, a 2x2 grid won’t reproduce the problem (hard edges in green; smoothing group numbers in white):
But a 4x4 grid will:
Here we should get four smoothing groups, but we only get two instead.
Today I followed up with our modeling department and it becomes a pressing issue for us. We discover more and more assets showing the described problem. Do you think you can provide a solution soon, or do we have to look for a workaround? Thank you again for your support.
I ran some tests today. It appears the problem is solved by the version of the XMesh saver you sent me. I will run some more test and let you know if I run into any issues.
