Mesh error only on mobile

Hi,

I have a mesh that gets stretched vertex only on mobile (preview and on the physical device).

Normal preview

Mobile preview

Exported via 3ds max 2015, FBX (2012-2013-2014), Edit mesh, all vertex welded.

What could be the problem? Thank you!

Edit: I tried exporting it as an .obj, and it just changes the stretched vertex to others. It seems random.

Edit2: So the problem was the vertex count. But watch out for the added vertices when importing in UE4. It’s not gonna be the same count as the one in your favorite 3d program.

Edit3: READ THIS: [Efficient Art Production: Theory and Practice][3]

Hi!

I think you must check number of vertices in your model. Because mobile content has restriction for vertex number. The number of vertices must be less then 65535. I recommend you to split your model into several parts and combine them inside UE4 in one object.

Mesh Limitations

There are certain restrictions on the mesh types supported on mobile platforms due to the hardware.

All mesh types can have up to 65k
vertices due to the lack of 32 bit
index support on mobile hardware.
Skeletal Meshes can have up to 75
bones.


That’s strange… It “only” has 50 965 vertices. I’m gonna reduce the count a bit and try again.

Edit: This is with 20 470 vertices:

Still here.

Okay I found out that in 3ds max it says 20 470 vertices, and in UE4, it says 75 215. I don’t know why.

This website is supposed to give the rule for vertex counting, but i’m not sure I follow.

Edit: After reading a bit on the subject, it has to do with the smoothing groups and the way UE4 calculates meshes. When you have a lot of different smoothing groups, your vertex count will go up more than if you had less smoothing groups. The way I see it is that UE4 calculates each smoothing group as kind of a mesh, or a surface. So it creates vertices for each of these corner surfaces, even if they are just one that is on the edge of multiple smoothing groups. If it makes sense.