Bilboard behind a 3D object TA | Forum

Bilboard behind a 3D object TAA\noise problem

Hey everyone. When I place a bilboard behind a 3D object (desk fo example) I get strange artifacts in that object some sort of noise. If I bump up TAA value up to 1 it disappears but the bilboard quality degrades seriuously. Is there a way around that issue? Would appreciate your help.UPD. I've uploaded the video where you can clearly see the problem. Tried different TAA setting (samples amount, velocity buffer etc.) in UE with no effect so farhttps://youtu.be/t-G1l9AnlNU

Andrew

Zoltan@Aximmetry

Hi Andrew,

If you place objects in front of the billboard, you have to take some steps to avoid visual artifacts. The reason is that Unreal uses Temporal Anti-Aliasing (TAA) to make the edges of objects look smooth. The problem with TAA is that it makes the billboard look very blurry, so we disable it where the billboard is. By default, TAA will also be disabled for objects that are in front of the billboard. The lack of TAA might make the edge of these object look jagged. If this happens you can turn TAA back on for these objects. How you do this depends on whether the object is opaque or translucent. These steps have to be done individually for each object that occludes the billboard.
- For opaque objects:
  - Select the object
  - In the Detail window, go to the Rendering section
  - Enable Render CustomDepth Pass
  - Set CustomDepth Stencil Value to 0
- For translucent objects you have to do some additional steps:
  - Go to the material editor by double clicking the translucent material in the Content Browser
  - In the Details window, enable Translucency / Allow Custom Depth Writes
  - Set Material / Opacity Mask Clip Value to 0 or some other small value This is the alpha threshold above which TAA will be enabled.

Note: For translucent objects, enabling TAA can make the billboard behind it look blurry. This is not a problem if the object is not too transparent or the affected area is not too big. Otherwise you have to make a tradeoff between the blurriness of the billboard and the quality of the edge or avoid these situations entirely.

Andrew

Thank you so much, Zoltan. That did the job.

magician

Thank you Zoltan. This is super valuable information.

Would be great to add articles like these to the documentation.

Zoltan@Aximmetry

Hi Magician,

The text is acutally an excerpt from the documentation
https://aximmetry.com/wiki/index.php?title=How_to_install_and_work_with_the_Unreal_Engine_based_DE_edition#How_to_create_your_own_projects

But it's true that it is hard to find this way, therefore we try to add these things to FAQ as well continuously.

Bilboard behind a 3D object TAA\noise problem

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