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Displacement Popping Issue


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Hey guys!, I'm running into an issue with my displacement popping during render time with all objects that have a material that's displaced. I can't seem to pinpoint the problem, other than that it occurs only when "True Displacements" is ticked on. It happens only along the edge of the geometry. The displacement is image based, on a mantra surface.

 

Here's a few frames of what I'm talking about.

 

Any help in trying to figure this issue out is greatly appreciated.

 

Thank you!

Edited by 7ofDiamonds
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you sure that's not co-planar polys?

 

edit: okay, watched it full screen now.  you might be displacing too much.  what is the image you're using?  my guess is that the overall displacement is all pushed out too far and so your poly boundaries are getting stretched.  note that this isn't just about the scale of the displacement so much as the "center" of the displacement.

Edited by fathom
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you sure that's not co-planar polys?

 

edit: okay, watched it full screen now.  you might be displacing too much.  what is the image you're using?  my guess is that the overall displacement is all pushed out too far and so your poly boundaries are getting stretched.  note that this isn't just about the scale of the displacement so much as the "center" of the displacement.

 

I'm using a TIF as the brick displacement (attached, with a HIP file).

Tried dialing down the displacement, but it still happens? I'm not sure if I get what you're trying to say about the center of displacement.

Weird thing is, I dropped in a box, very similar in dimensions, and plugged the same material into it, I'm not getting that issue at all...

post-12698-0-29286100-1454266934_thumb.j

disp_issue.zip

Edited by 7ofDiamonds
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Was able to fix this by adding a Facet SOP and checking PreCompute normals on. I'm not sure how it fixed it, but if anyone has an explanation, would like to know what actually happened...

 

**EDIT**
That actually did not fix it, made some really bad lighting artifacts instead.

Edited by 7ofDiamonds
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your texture looks like it's got a value of something just shy of 1.0 pretty much everywhere aside from the mortar lines.  that means you're displacing your geometry pretty much everywhere directly away from the face of the geo.  when you have an outside corner, each face moves out and you get that stretched artifact between the two faces.

 

for bricks like this, you should make a texture where your bricks are black and any your mortar lines are white (or some value above 0 -- higher values being deeper crevices).  then displace with a negative scale.  that way, your displacement doesn't change the basic geometry where it doesn't need to and your corners will still line up properly.

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