Displacement map reder errors

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This is the first time I have tried using displacement maps and am getting odd errors that mantra or lighting changes don't seem to fix.

The errors are chunky shadows and black triangular missing regions from the surface. To see what I'm seeing, look at the attached image.

It's a simple scenario, but I attached the hip file is attached as well.

I found an older post about the problem that mentioned tweaking params in mantra, but H9 removed or moved those params.

Any one else run into this problem?

Attachments:
displacement.map_error.hip (162.5 KB)
render_with_errors.jpg (24.9 KB)

~adam
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Hi adam , Hope this helps

1 You need to add a property ( displacement bounding ) either at the shader level or add it to your geometry node. If you look at some of the displacement shaders that are shipping with H9.1 you can see the bounding property. It caught me out when I started messing with displacements.
It can be added it via the flyout menu ( little cog )on the geometry node under rendering parameters. If its missing it causes those black areas that look like holes

2 Up the dicing value on your geometry node

3 Use a 16 / 32 bit image file that uses the .rat format

4 In your Rop beef up your pixel samples higher than 3 / 3

If all this fails there is a great thread over at od force , with lots of scene files including one I have put up showing all sorts of displacements
http://forums.odforce.net/index.php?showtopic=6517 [forums.odforce.net]

R
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Thanks for the quick and detailed reply!

The displacement bound param fixed the missing poly problems, and I'm sure your other thread and mucking around will reveal why those square shaped shadows are appearing on such a flat surface.
~adam
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I tried all of the tricks that were passed around in the other forums like adding extra params around dicing and pumping up sampling and shadow resolutions with out luck.

The two params that did the trick in eliminating those nasty 2 bit square wave shadows was increasing the Shadow Quality and Shadow Softness options in the light that is casting the Depth Map Shadows.

Additionally, after testing different angles, I noticed that the edges of shadows cast from peaks were getting choppy and bumping up the Pixel Samples in the Depth Map options in the lights smoothed it all out nicely.

Feels so good to start getting traction with rendering!!

P.S. The fixed HIP is attached.

Attachments:
displacement.map_fixed.hip (166.3 KB)
render_with_fixes.jpg (23.5 KB)

~adam
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