I've been running into an issue with the Karma Hex-Tiled Triplanar node and was wondering if anyone else has experienced the same problem or found a workaround.
The issue:
Whenever I use Karma Hex-Tiled Triplanar for both Base Color and Displacement at the same time, the
render shows horizontal scanline-like artifacts across the entire textured surface.
If I disconnect either:
the Base Color, or
the Displacement,
the artifacts disappear immediately.
Interestingly, this only seems to happen with the combination of Base Color + Displacement. Using the same node for Roughness, Specular, or Normal does not produce the issue.
What I tested
- Houdini 21.0.512
- Houdini 22.0.368
- Houdini 22.0.396
- Houdini 22.0.397
I reproduced the issue on two different PCs (my own workstation and a university PC (only 21.0.512)), so it doesn't appear to be machine-specific.
I tested with:
Megascans JPG textures
Original Megascans 8K EXR textures
Both produce identical results.
I also experimented with:
Karma CPU and XPU, different Dicing Quality Scale values, various render settings. None of these resolved the issue.
One interesting observation is that with Dicing Quality Scale = 1 the artifacts are still present but much less noticeable. Increasing the value to 2, 3, or higher makes the scanlines significantly more visible.
Comparison
If I replace the Hex-Tiled Triplanar node with the Hex-Tiled Texture node, the problem disappears completely while producing the expected result.
Images
I've attached a PDF containing all of my tests and comparisons.
Has anyone else seen this behavior?
If so:
- Were you able to reproduce it?
- Is there a known workaround?
- Or does this look like a bug in the Hex-Tiled Triplanar node?
At the moment, the only workaround I've found is to avoid using the Hex-Tiled Triplanar node and
instead use the regular Hex-Tiled Texture node.
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Any ideas or suggestions would be greatly appreciated!