Tri-Planar Projection UV Seams issue

[Robot_and_Robot]

Hi Everyone, 
I ran into an issue with Substance Painter.
I am projecting a texture on my character model with Tri-planar however it still somehow reads the UV seams of my model and that results in, well... seams. Please see attached image.
Is there a way to get get Tri-Planar to work as intended?

*For instance, when using Tri-Planar in Redshift, it will ignore the original model's UVs and I wouldn't have this issue. Example Attached.

Thank you!

[davescm]

Is there a significant difference in texel density between those two areas i.e a big difference in scale on the UV map? The issue in your pic looks more like the texture being applied evenly (i.e seamlessly) using tri-planar but in a much lower resolution at the back of the head.

I can simulate that on a simple sphere where I have scaled two quarters one up and one down in the UV map. Tri-planar applies the texture seamlessly but the seam becomes visible because of the differing texel density.

Dave

[Robot_and_Robot]

Thank you for your reply Dave!
This is exactly the case, the texel densities have an x4 difference. I can, of course, fix it in my 3D application and adjust the texture image files accordingly. But in order to preserve the texture's fidelity and have an even texel density, some of the tiles' sizes will increase from 4K to 16K with most of the space being just empty.
What I find weird is that Substance Painter takes this density into consideration when having a Planar/Tri-Planar/Spherical, etc projection. No other software that I work with (Houdini / C4D) considers the texel density with these types of projections. Usually the above mentioned projection techniques override the object's original UV settings.

I wonder if there's a "magic switch" somewhere in Substance Painter that will allow us to ignore the original density.

[davescm · Accepted solution]

It is not a question of taking it into consideration, if the same size areas on the model take up significantly different size areas on the UV then, whatever resolution the exported maps are set to, those areas are going to look different.

One thing you could do though is to take advantage of the ability to set Painter to set different UV tiles, using the UDIM workflow, to different output resolutions. So, for example, the same material can use 4K on tile 1 and 1k on tile 2

Dave

[Robot_and_Robot]

I had no idea that was possible. This is exactly what I was looking for. Problem solved!
Thank you SO MUCH Dave!