Curvature maps and convexity

Torch

Hey guys, I've been messing around with Substance Designer and Knald lately and had a couple of questions. I've taken a look at the wiki about curvature maps but wanted to know - what is the main use for them? Some people have said they're useful for highlighting and accentuating the edges of model, so they can be used as an extra layer on the spec map to make the edges pop more. Some also mentioned it can be used for masking edge wear, e.g. scratches or metal being chipped away on the edges of a model. Can anyone who's had experience in using them give some brief info about them?

Also, when using Knald I've seen tabs for 'concavity' and 'convexity', I understand that Concavity is probably referring to 'cavity' maps, but how exactly are convexity maps used? Thanks

Jerc

Concavity and convexity maps are the 2 parts of a curvature map.
If you take a Curvature map from SD, the range from 0 to 127 would be a concavity map, and the range from 128 to 255 would be the convexity.

I mainly use curvature for what you described: any sort of wear and tear, edge highlights, chipped paint, that kind of thing.

MM

Torch wrote: »

Also, when using Knald I've seen tabs for 'concavity' and 'convexity', I understand that Concavity is probably referring to 'cavity' maps, but how exactly are convexity maps used? Thanks

Knald is great at creating all these maps.

i use the convexity maps to create masks for edge ears which can be used to paint roughness/gloss maps easier and specular highlights etc. you can just copy the convexity from Knald to an alpha channel/load selection and use it as a layer mask.

instg8r

Just want to make sure I'm clear....so if I can get a concavity and convex map from Knald, is there a need to bake out a curvature map?

MeshMagnet

In XNormal you have two options when baking out a Curvature map. There's one that looks black and white and one with color information.

Could someone explain what's the difference?

Jerc

The difference is that in one case, the concave and convex parts are encoded in 2 different color channels, while the greyscale one encode concave parts in the 0-127 range and the convex parts in the 128-255 range.

EarthQuake

Wrote a bit about this and posted a short tutorial for spiting the crazybump/sd style single channel curvature maps into two separate maps:

http://www.polycount.com/forum/showthread.php?t=140861

As noted above, concavity maps are great for masking pits and areas where dirt or dust would collect, while convexity maps are great for masking edge wear, scratches, etc.