Narrow linear artifacts in Point Density volume when rendering on GPU #48007

New Issue

Kevin Healy · 2016-03-30T20:26:43+02:00

Kevin Healy commented

2016-03-30 20:26:43 +02:00

System Information
Windows 7 64-bit with dual NVIDIA GeForce GTX 960

Blender Version
Bug appears in 2.77 release of March 19, 2016 and in 2.77 build of March 27, 2016 (Hash #211b539)

Short description of error
When rendering on GPU, narrow linear artifacts appear in a volume with a Point Density texture. The artifacts appear in both Rendered Viewport Shading and in a Rendered image (F12). The artifacts are not present with CPU rendering.

The artifacts appear if the Mode for the Point Density texture is set to Object Vertices or Particle System. They appear if the Point Density texture is applied to any of the volumetric Shaders (Emission, Absorption, Scatter).

Rotating the source Object (mesh or particle emitter) illustrates that the artifacts are always in the Object's local Z direction. The rotation of the domain object with the Point Density volume material does not affect appearance of the artifacts.

The artifacts only appear to originate from the object vertices or particles with the largest or smallest Z values. Vertices or particles at other locations in a particle distribution or in a mesh do not generate the linear artifacts.

Exact steps for others to reproduce the error
This image illustrates the linear artifacts with a cube as the source Object of a Point Density texture. Here all four upper vertices generate the linear artifacts:

This blend file point-density-Z-bug.blend illustrates the artifacts generated by a subdivided Cube object and a Particle System emitted from the Plane object. The Domain object holds a volumetric material called "PD Emit". Both an Object Vertices texture and a Particle System texture are set up within the Domain object's material by connecting the desired Emission Shader to the volume Material Output. The artifacts appear in Rendered Viewport Shading and in an Render using GPU, but not CPU.

Rotating the Plane or Cube objects in Object Mode rotates the direction of the artifacts. Rotating the mesh of the Plane (or Cube) in Edit Mode changes which vertices or particles generate artifacts but the artifacts remain pointed in the Plane (or Cube's) local Z direction.

**System Information** Windows 7 64-bit with dual NVIDIA GeForce GTX 960 **Blender Version** Bug appears in 2.77 release of March 19, 2016 and in 2.77 build of March 27, 2016 (Hash #211b539) **Short description of error** When rendering on GPU, narrow linear artifacts appear in a volume with a Point Density texture. The artifacts appear in both Rendered Viewport Shading and in a Rendered image (F12). The artifacts are not present with CPU rendering. The artifacts appear if the Mode for the Point Density texture is set to Object Vertices or Particle System. They appear if the Point Density texture is applied to any of the volumetric Shaders (Emission, Absorption, Scatter). Rotating the source Object (mesh or particle emitter) illustrates that the artifacts are always in the Object's local Z direction. The rotation of the domain object with the Point Density volume material does not affect appearance of the artifacts. The artifacts only appear to originate from the object vertices or particles with the largest or smallest Z values. Vertices or particles at other locations in a particle distribution or in a mesh do not generate the linear artifacts. **Exact steps for others to reproduce the error** This image illustrates the linear artifacts with a cube as the source Object of a Point Density texture. Here all four upper vertices generate the linear artifacts: ![point-density-Z-bug.png](https://archive.blender.org/developer/F299613/point-density-Z-bug.png) This blend file [point-density-Z-bug.blend](https://archive.blender.org/developer/F299615/point-density-Z-bug.blend) illustrates the artifacts generated by a subdivided Cube object and a Particle System emitted from the Plane object. The Domain object holds a volumetric material called "PD Emit". Both an Object Vertices texture and a Particle System texture are set up within the Domain object's material by connecting the desired Emission Shader to the volume Material Output. The artifacts appear in Rendered Viewport Shading and in an Render using GPU, but not CPU. Rotating the Plane or Cube objects in Object Mode rotates the direction of the artifacts. Rotating the mesh of the Plane (or Cube) in Edit Mode changes which vertices or particles generate artifacts but the artifacts remain pointed in the Plane (or Cube's) local Z direction.

Kevin Healy commented

2016-03-30 20:26:43 +02:00

Changed status to: 'Open'

Kevin Healy commented

2016-03-30 20:26:43 +02:00

Added subscriber: @KevinHealy

Lukas Tönne commented

2016-03-31 09:05:23 +02:00

Closed as duplicate of #47794

Lukas Tönne closed this issue

2016-03-31 09:05:23 +02:00

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Narrow linear artifacts in Point Density volume when rendering on GPU #48007