Substance Painter baking AO weird issue (dark spots)

lopan

Hello

I tried to bake AO with the default settings and it yielded strange results. it gives some dark spots as shown in the images. The only thing I changed is to "use low poly mesh as high poly" and size to 2048. 

Ps. I'm only using a high poly mesh (around 1 million points), as I couldn't find a nice way to obtain a low poly mesh out of a high poly one in ZBrush. I used the decimation master but the normal map generated was very messy for some reason, so I gave up using the low/high poly workflow as I'm only interested in a static render and my system could handle it well enough. 

I'm fairly new to SP and ZBrush. Not using a low poly mesh could produce those artifacts? 

Thanks in advance.

poopipe

show UVs it's probably that 

lopan

Thanks, this is driving me nuts.

I analyzed the UV and it seems that for some reason ZBrush is unwrapping  the model twice. It'a a tool with a single subtool (merged for importing into SP with 'Merge Visible'). I just selected this single subtool and chose Unwrap in the UV Master menu. Any ideas why this is happening?

I painted a stroke on the face and it's showing on 4 distinct 'islands'.

EDIT: I found out what the problem was. Actually, this mesh is a mess inside. There is stray mesh inwards the main mesh and lots of flipped normals. Probably, I left that option 'double' checked while extracting the mesh in ZBrush several times . Don't bother, I'll trash this. Total loss.