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Adaptive subdivision with external displacement map fail
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Description

System Information:
Operating system: Windows 8.1 64-bit
graphics card: Nvdia GT620

Blender Version:
Broken: 2.78 95cb714 (Release Coordinate)

Short description of error:
External displacement map (mainly 32-bit full float EXR or 16-bit TIFF) lead blender failure without any message.
Using Cycles procedure map will not cause any error. This bug only occur when using external textures.

Steps leading crash:
01. Adding Catmull-Clark Adaptive Subdivision Scheme to the mesh (Assumed mesh already has UVs)
02. Adding Diffuse BSDF
03. Adding Image Texture node to Displacement plug
04. Software broken.

Subdivision Scheme: Both Subdivision and Adaptive Subdivision has been tested. Both broken
Displacement Mode (Work sometimes): Bump
Displacement Mode (Broken): True and Both

Details

Type
Bug

Event Timeline

Thomas Dinges (dingto) triaged this task as Needs Information from User priority.

Please follow the bug submission guidelines and attach a blend file and the texture that you use here, so we can easily reproduce the issue.

I have the same problem. the external displacement map often make blender crash in the Experimental feature, like connect the node, switch the displacement mode, than crash :(

Texture included inside blend file.

Sorry for making trouble

Are you rendering with the CPU or GPU?

The dicing scale in this file is 0.1, which corresponds to 100 polygons per pixel, that's way too much for most scenes. On a GT620 card which only has 512MB or 1GB of memory you'll run out of memory very quickly. It doesn't necessarily explain why an EXR fails and a procedural texture works, as the texture in this file only takes up 16MB. Though it could be that it pushes it just over the edge and makes Cycles run out of memory.

What does fail without any error message mean exactly? It renders black? Is that in the viewport, final render, both?

Brecht Van Lommel (brecht) renamed this task from [RC MicroDisplacement Bug] External Displacement Map Fail to Adaptive subdivision with external displacement map fail.Sep 4 2016, 1:26 PM
Thomas Dinges (dingto) raised the priority of this task from Needs Information from User to Normal.Sep 4 2016, 3:59 PM
Mai Lavelle (maiself) claimed this task.

Possible duplicate of T49252, tho I don't have enough info to reproduce. I think I might have an idea whats going on, but might take a bit to find the cause. Problem could be in how images are updated for displacement.

@Mai Lavelle (maiself) I can confirm this, the step flow:

  1. Download the Displacement.zip file form MarcoCheng;
  2. Open with blender 2.78rc and switch to the material tab in the Properties Editor,
  3. swith the displacement mode from True to both, than back to True, than blender will crash.

and sometimes happened when I switch to the material tab, or connected the node, or scroll the material panel, often crash with external displacement maps , it's make blender not stable, only happen with the adaptive subdivision, but the procedural maps is work well, sorry for my bad English, hope this can helpful.

@Brecht Van Lommel (brecht) Just Rendered with CPU experimental Mode.

I'm sure that crash isn't related to dicing scale (whatever value you use). When I create a simple plane with UVs, add a subdivision modifier and load the displacement map (switch to True Mode), Blender will crash immediately even not switch to RenderMode/Click the Render button.

Mai mentioned that she fixed a crash related to use of image textures today.

I would download the new buildbot build ( hash 14e4747) to see if the issue is fixed for you as well (it is for me).