Exported Pivot Painter Mesh Missing UV Channels

Hi There,

I’m having an issue where the mesh I exported from 3DS Max with the Pivot Painter tool is missing some UV channels. When I compare it to some of the examples from the Content Examples (tree), they come with 4 or 5 UV channels where I only get 3.

My workflow on a basic object with two pieces is (after setting pivots) select child set, pick parent and Paint Current Selection. In 3DS Max I do see some Alpha and Color Information but when I check the UVs in UE4, I only get 3 sets. Is there a step I might be missing when I use the Hierarchy Painter?

Not sure if this is the proper forum to ask since it has to do with a 3ds Max script. let me know if it’s not and I can move it.

Thanks!
Tam

I’m not quite sure if I understand properly. Does the shader not function properly? Is there not any UV data in those channels when viewed in 3ds max with the channel info utility?

I’m not sure if this factors into your question or not but just as a note 3ds studio Max’s uv channels are 1 based and Unreal is 0 based. Which means uv 1 in 3ds max = uv 0 in unreal. Which could be misleading if you were comparing the two.

Do you think you could share your max file?

Thanks for the quick response!

Sorry, my question was probably worded poorly. I think this might be a non issue as I might have confused myself. I originally was checking the number of UV sets in Maya because I’m not very 3ds Max versed and I have no idea how to view the number of UV sets in 3ds Max. In Maya I was only getting 3 UV channels which was confusing as I was comparing it to an exported version of the Tree asset. But when I imported the asset into UE4, a 4th UV set was generated. I don’t really understand why but it might have something to do with what you mentioned with UV channels in UE4 are 0 based.

I was more curious as to why there were differences in the number of UV sets among the examples provided versus the ones I was creating. Wasn’t sure if I was missing a step or not.

I attached the .max file if you wanted to view it. I also attached a screen of what I see in Maya and UE4.

Ah, I see. Sorry, about the late response.

The pivot painter script puts information in the vertex colors, uv channel 2 and 3. It skips 1 and 0. 0 is reserved for actual texture coordinates and uv 1 for lightmap uvs.

When imported Unreal preserves the uv channels. So even though uv 1 contains no information Unreal retains that channel position. So it looks like unreal has 4 channels worth of data but the model only actually contains 3. It looks like Maya ignores uv channels that don’t contain info so it looks like maya only shows 3.

i’m not sure this is still true is it?

exporting the pivot painted tree from the content examples and reimporting into my own project seems to remove some of the required UV data for the material nodes to work…

looking at the model in max and maya it seems the data has been exported correctly, just isnt there when imported.

I have seen this as well. It looks to be a bug. You can fix the issue by adding uv data to uv channels 0 and 1.

I have seen this as well. It looks to be a bug. You can fix the issue by adding uv data to uv channels 0 and 1.