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Transferring Polypaint texture down to low poly model

ZBrush Usage Questions
#1

Hi guys,

I’m still fairly new at this, and I’ve been struggling all day with this polypaint issue.
I’ve created a character intended for VR chat with polypaint details on top. I need to decrease the polys to less than 20k, but I’m having a lot of trouble transferring the polypaint texture from the HD to the lower detail.

I’m not incredibly confident with UV’s as yet, but when I go to unwrap them on a clone for the HD model, it all looks fine. I’ll then create a duplicate of the HD model, bring it down to the desired subdivision level and create the UV’s. The UV’s are significantly different from the original after I unwrap them.
I’ll then go down to texture map and load up the saved texture from the HD model, and it doesn’t line up properly at all.

In the beginning, I may have tried to create my own seams after following along with a tutorial. Not certain whether that’s my issue here or not. Either way, I’m struggling to mimic those seams on the lower detail model.
I also get the same issue with all of the different items of clothing; the UV’s just won’t line up.

I’ll include some pictures of my model so far, the two different UV’s and finally the unaligned texture.

I’ve had a go at using xNormal to do this, but couldn’t get that to work either.BigLezHD.pngBigLez01.pngBigLezLowPoly.pngBigLezLowPolyUV.jpgMessedUpUV.jpg

Attachments

BigLezLowPolyUV.jpg

MessedUpUV.jpg

#2

If you’re baking in xnormal then don’t worry about trying to align the UVs of two different models. Really only the lowpoly game model needs UVs - the painted sculpt does not.

First off make sure that both models are occupying the same space, then export each one (polypaint should be visible on the highpoly mesh when you export it). Load both models in their respective slots in xnormal. You should be able to keep the default settings for the the lowpoly mesh, but for the highpoly mesh you’ll want to make sure that “Ignore Per-Vertex-Color” is NOT checked (polypaint is vertex colors, so you do not want it to be ignored for this bake). Then for the baking options, make sure that the “Bake Highpoly’s Vertex Colors” map type is enabled, then generate your map. This will bake the polypaint colors from the sculpt to the lowpoly’s texture.

If you decide to use xnormal to bake additional map types like Ambient Occlusion or Normal maps, then you might have to re-enable ‘Ignore Per-Vertex-Color’ when baking those map types.