Bug Splat when I try to render material with displacement map

[mjm223]

I have an older version of VRay (Version 1.0074, I believe) for SketchUp 6.

-In the Material Editor, I added a VRay Linked Material (Ashlar Brick).
-Under the "Maps" tab I click the check box for Bump then clicked the "m."
-I set the type to "Bitmap," upload a grayscale image of the texture that I created in Photoshop, and set the multiplier to 0.6.
-I clicked "Apply" then checked the "Displacement" box in the "Maps" tab and clicked the "m."
-I set the type to Bitmap, uploaded the same grayscale image, and set the multiplier to 2.
-I click "Apply."
-In the Render Options menu, in the Displacement tab, I kept the default settings:
Edge Length: 4
Max Subdivs: 256
Amount: 1
Relative to bbox: Unchecked
View-Dependent: Checked
Tight Bounds: Checked

My Primary Rendering engine is IR, secondary is LC, both have default settings for a single frame rendering.

When I click the render button, the light cache calculates for about 3 minutes, then I get the Bug Splat.

Does anyone know what's causing it to Bug Splat?

Is this problem fixed in the newer version (V1.05.30)?

[thomthom]

Re: Bug Splat when I try to render material with displacement map

Are you applying the displacement on a very large plane? If so, sub-divide it. You could be running out of memory.

[mjm223]

Re: Bug Splat when I try to render material with displacement map

It is on a fairly large plane. By "subdivide" do you mean reduce the subdiv value?

[thomthom]

Re: Bug Splat when I try to render material with displacement map

No, split the face into smaller faces. If the face is too large it'll eat up too much memory.

[mjm223]

Re: Bug Splat when I try to render material with displacement map

I see, in that case, I'm not totally sure. What I did was I used the sandbox tool to create smooth surfaces from the topography. The topography is now one big curvy blob shell, but when I turn on the Hidden Geometry, I can see that the huge blob shell is just hundreds of triangles. Does that still make it one big surface?

[dalomar_cg]

Re: Bug Splat when I try to render material with displacement map

If you could possibly separate that object into smaller collections of triangles that would certainly be helpful. Generally 2 things wind up being the cause of a lot of displacement crashes. The first is having one big face, which V-Ray doesn't like since displacement must be done on a per face basis. Splitting that face up allows V-Ray to take smaller bites rather than one huge one.

The other is just having a very large displaced object. When initially calculating the mesh, V-Ray needs to keep as much of the displaced mesh in memory as possible so that it can calculate adjacent faces so that edges can match up. If there are too many faces that V-Ray has too keep around (or better the displaced mesh on those faces is too dense), then V-Ray will run out of memory needed to calculate the whole mesh.

I believe (although I have not tested this), that disabling Keep Continuity will minimize the number of faces that V-Ray needs to keep in memory when initially calculating the mesh. This could very well be a complete facet of my imagination though, so don't take that as 100% correct.