Displacement + Normal map problem

Fri Jun 13, 2014 2:42 am

Displacement map can't work with bump or normal map together, because of too complex math.
What is the point of using them together?

Fri Jun 13, 2014 2:52 am

Karba wrote:Displacement map can't work with bump or normal map together, because of too complex math.
What is the point of using them together?

The point is to enhance the micro-details on the surface. Using a Displacement as general forms, and then apply a detailed normal map on top, with a different tiling, to have super close-up details. It's similar to what you would do with a detail maps in a video game.

Fri Jun 13, 2014 3:25 am

I was thinking the same. In ZBrush, I'd create a displacement map from level 1-4 (for example). And the bump or normal map would be the detail contained in level 4-6 (say). Then in LW, displacement would be put on subD base object, giving main form and normal or bump giving the detail. Perhaps this is old thinking with sub-poly displacement?

Fri Jun 13, 2014 3:42 am

gordonrobb wrote:I was thinking the same. In ZBrush, I'd create a displacement map from level 1-4 (for example). And the bump or normal map would be the detail contained in level 4-6 (say). Then in LW, displacement would be put on subD base object, giving main form and normal or bump giving the detail. Perhaps this is old thinking with sub-poly displacement?

why don't you put 1-6 to displacement?

Fri Jun 13, 2014 4:15 am

Karba wrote:why don't you put 1-6 to displacement?

You can certainly do that if the displacement is from a 3D model, like something made in ZBrush. The displacement I'm using is generated by photometric stereo, so you don't have the same level of detail as you would have in a hand-made model. Sure, you could apply the displacement in ZBrush, do some additional detail sculpt, and export the result as an 8K displacement, but that takes time. If we could simply apply a detail normal map, with a different tiling, on top of our displacement, that would be much faster and easier. I hope you understand my point.

Fri Jun 13, 2014 6:28 am

edited and removed by user

Fri Jun 13, 2014 9:07 am

Karba wrote:
gordonrobb wrote:I was thinking the same. In ZBrush, I'd create a displacement map from level 1-4 (for example). And the bump or normal map would be the detail contained in level 4-6 (say). Then in LW, displacement would be put on subD base object, giving main form and normal or bump giving the detail. Perhaps this is old thinking with sub-poly displacement?
why don't you put 1-6 to displacement?

What I was saying was this WAS how it would be done. The reason was you need the subDivision levels (or geometry) to show the displacements. So you would only do it to a certain level, before making the rest bump or normal.

However, if i have models that were created in this old way, I will still need to mix and match. And, I still want to be able to use bump or normal (from existing assets) without the shadow terminator issue.

At the moment, with stuff from ZBrush neither are working. With bump or normal, I have the shadow issue. With Displacements I have the mesh tearing issues. Both need fixed as far as I'm concerned.

Fri Jun 13, 2014 9:14 am

The "tearing issue" cannot be fixed, it's a limitation of the displacement. You can workaround it by painting the edge of your UVs with a flat value in the displacement map, so they won't tear apart.

Fri Jun 13, 2014 12:29 pm

Karba wrote:Displacement map can't work with bump or normal map together, because of too complex math.
What is the point of using them together?

OK. I am not claiming to understand why after your statement that bump or normal map together doesn't work. But on my end Displacement, Bump or Normal are working fine together. At first they were not and I thought it was a rayepsilon issue. I put in .01 and then .001 and keep just adding a zero in it won't take the actual number and then I added one more zero to make .0001 the value set back to zero but it didn't because everything worked from that point on. I just changed the scene rayepsilon to zero after reading this post and it messed up the scene. Tried the zero trick and all is well again. Bump or Normal and displacement are all working together correctly.

I uploaded the test results. This was just a quick simple scene setup for testing, I put the render in clay mode for better clarity on the maps.

I will try other scenes later to make sure this isn't just some fluke.

Fri Jun 13, 2014 1:28 pm

Karba wrote:Displacement map can't work with bump or normal map together, because of too complex math.
What is the point of using them together?

i am doing character modeling and render all the day. if we can't use Bump and displace at the same time, doing professional characater work with Octane will not be possible.
some info : http://www.cgfeedback.com/cgfeedback/sh ... ro&page=25
or ask mr Debevec.