Cavitty map help

Tim1

Hi, I'm having problems converting my normal map into a cavity, It's not giving me the full result.

I normally use Phillip K's method explained here: http://www.philipk.net/tutorials/materials/metalmatte/metalmatte.html
and will work fine but for this map it's not doing it.

Here's a preview of the Normal,




This is what it looks like when I run in through Xnormal's photo shop filter, you can see it has faded in parts,


If I run the process through the actual Xnormal application with the same settings I get a different result which look like it fills in the gaps of the original but there's no nice way of merging them both, any ideas?





I've also tried NDO2 and get the same result.

Eric Chadwick

You can combine them in Photoshop if you use one of the layer blending modes, Overlay for example.

But your normal map looks odd. The bevels seem very weak. What do the high-poly and low-poly models look like for this part of the map?

Tim1

Eric Chadwick wrote: »

You can combine them in Photoshop if you use one of the layer blending modes, Overlay for example.

Yeah I think I'll just have to do it that way, was just hoping to get a clean cavity texture.

Here's the high and low for ref, the normal seems to work fine in unreal though.








I baked it down in Xnormal using a cage from the low poly, seemed to produce the best results from the methods I tried

Eric Chadwick

Everywhere you have hard edges on your low-poly, you need splits in your UVs, and some space between those UVs. This gives the normal map enough pixels to represent the sudden change in direction. If you don't split, the normals are twisted suddenly as they cross that threshold, which causes shading errors.

The Xnormal baked cavity map... is that baked from the high-poly model? It looks very odd.

Eric Chadwick

Some info here that might help you.
http://wiki.polycount.com/wiki/Curvature_map

Tim1

Cheers, I'll have another look at my UV's and give it a go

The cavity was done by running the tangent normal through the normal to cavity options, I'm just giving substance painter a go and from tutorials on youtube the cavity map looks useful for some of the texturing tricks so was trying to get one in.

I've heard of curvature maps but never really tried using them in my workflow, is it worth it?

Eric Chadwick

Yes, you get much better results than trying to convert a normal map, because you're using the actual geometry as your source.

A normal map does not store cavity/convexity information, it only stores slopes. So any converter has to try to read the slope data and approximate curvature from that. As you found, they pretty much suck at it.