Opacity Mapping Not Working Correctly in OSPRay

ParaView Support
1

Hey everyone, i’m trying to add some simple 3D geometry with textures mapped to a scene in OSPRay.

I am using the simple bush from this site: https://www.cgtrader.com/items/997157/download-page

Loading it into PV and applying it as a PBR texture works fine, although it breaks when OSPRay is turned on. OSPRay is still rendering the parts of the plane even though it should have 0 opacity, see picture below.

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image1276×467 140 KB

Anyone have any suggestions to try? Or is this just another core OSPRay bug? This would be a great functionality to have to add more detail to scenes.

2

Hi,
Which ParaView version are you using?

3

Hey Michael, I have tested it and found it in both 5.8 and nightly versions since then.

4

OSPRay 2.x integration have been merged to VTK.
It is not in ParaView yet though. We will see if this bug is fixed by OSPRay version bump.

5

Great! That 2.0 bump has a couple other bug fixes that will be great to have. @Michael do you happen to know if full integration will happen before or after 5.9?

@Dave_DeMarle do you happen to know if this bug is fixed in 2.0 or is on the radar to fix? This is a feature that would be great to have to build more complex scenes within OSPRay itself. I can file something more official on gitlab if need be.

6

Since it is already in VTK, I think the plan is to have it in ParaView 5.9.
Note that the bug is most likely in VTK, not OSPRay. I’m sure that translucent textures were supported at some point.

7

PV 5.9 will have OSPRay 2. Likely 2.2.1 or later since 2.2.1 is intended to bring back some features for PV/VTK.

Please do file (or search for and then file since this sounds familiar) a bug regarding opacity. I agree with @Michael that the problem is most likely in VTK’s mapping to OSPRay calls.

8

Great to hear that it should be in 5.9. I’m going to be hopefully bringing in a lot of new users from my company in 5.9 so the more OSPRay capability the better.

Appreciate the help guys, I’ll file a bug for this on gitlab.

EDIT: Gitlab Link: https://gitlab.kitware.com/vtk/vtk/-/issues/17960