I’ve been testing out the GEO TOOLS Open SubDiv feature and I’m not sure if there will always be a lack of synchronicity between UE4 and 3rd part implementations, but I get the following results.
If I make a cube in 3DS MAX it has 6 quads and 12 Tris. Importing results in the 12 tri mesh, which is as expected. However, in 3DS MAX, if I add one level of Open SubDiv, I get 48 Tris. In UE4, the result is 72 Tris.
If it is sub dividing, we should see a 4X poly count increase, not 6X
Furthermore, the bounds of the mesh in MAX remain the same, at the first level of subdiv, which is not the case in UE4. Increased levels in 3DS Max will reduce the size of the mesh.
The hope was is 3rd party applications and UE4 and the same results, and UE4 used the GPU for Open SubDiv, then lower poly meshes could be set up with proper heightmaps for displacement outside of UE4 and then replicated in engine.
Thanks for the response. It is true that 1 and 3 are essentially the same in tri count, they do not result in the same mesh, and that is the problem. For example, if you want to run a test of subdividing and applying deformation with a height map, it will not have the same result as doing the same process in editor.
I talked to one of our devs about this and he mentioned that we use the same algorithm, but with different configs. I put in a feature request (UE-47346) to match up our SubDiv configs with Autodesk before it comes out of “experimental” status.
