Genesis 8 displacement map seam solved

naughtyroad

(if this pops up twice: first post and my finger slipped halfway the first sentence, posting it by accident; I'll delete the half version if it goes through moderation)

So, I'm quite new to DAZ3d and 3d modeling and rendering in general. I was pottering around with displacement maps (background HSV 0,0,50), and I noticed that applying a bump map to the torso results in a thin but distinct seam along the edge with the arms (and presumably other edges as well). So a googled a bit on formum posts to solve this but nothing really came up (some discussion, but no real solution). I ended up solving it, and here's how for the next person to run into it:

So the trick is to apply some blank displacement to the other surfaces as well. Whatever misallignment the displacement map causes, it then causes it in both and they align again. But, don't just to apply the map; set the same displacement strenght, min/max values and presumably sub-D as wel.

Attached image 1 is what it looks like with a pure grey displacement map (HSV 0,0,50, or RGB 127,127,127), on just the torso (with strength 6 and the rest to default)

And attached nr 2 is the same settings applied to the arms too, as you see it's just a hint from where the other textures don't quite match up, but the seam is gone.

Richard Haseltine

The trouble is, with the default values (remember that "mid-grey" doesn't have a value as such, it's dertermined by the white and black points) [127, 127, 127] is just shy of a value of .5, and [128, 128, 128] is just past, so you can't hit a literal zero displacement that way. Real displacement maps are usually 16 bit rather than 8 bit, which (especially once there's a colour map too) should largely avoid the issue.

naughtyroad

Hmm, so it seems I've discovered a workaround for working with faulty displacement maps then. :)

Up untill now, I've mostly been using Paint.NET and it seems that's only doing 32bit ARGB. Guess I'll have to switch over to GIMP.

 

Pickle Renderer

If anyone else comes here with negative displacement issue, I set Minimum to -5, Maximum to 5, then made the image 16 bit greyscale in GIMP, with the background where I didn't want any displacement mid grey (50%).  There were no seams on my mesh in iRay and there was negative displacement where I wanted it.