Nanite Displacement/Tessellation vs DBuffer

Development Rendering
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1

Hi, I was looking at Nanite Tessellation/Displacement with the DBufferA. What I was trying was to get the red channel to input in the material as a displacement modifier but it doesn’t get any value when plugged in the Displacement and in the repro project it is plugged in the Metallic to see where it should be modifying the Displacement. I’ve done the test in 5.5 and 5.6. Is there a current limitation with DBuffer and Displacement.

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cheers

2

Steps to Reproduce
Open the project done in 5.6 and you will see the problem

3

Hi,

thanks for reaching out and providing a repro project. It’s currently not possible to have decals affect the displacement of Nanite tessellated geometry, since decals read the depth buffer for projection and cannot alter anything that would impact the depth buffer (including Nanite tessellated displacement).

A workaround is to write the decal into the displacement attribute of a runtime virtual texture, which can then be sampled inside the material used by the Nanite tessellated geometry and blended with its displacement. Please let me know if you need help with that.

Best,

Sam

4

yeah I was sure it was something about pass not being accessible. I was trying to pack my RGB to not create a new RVT.

thanks!

5

quickly check for writing to RVT via Decal but you can’t but anyway I was using mesh to write to it

6

Thanks for getting back. Do you need more help with the Decal-to-RVT approach?

Sam

7

If there’s a way sure I want to know :slight_smile:

8

Sure, here are some screenshots of a simple project I made which combines a decal texture with Nanite tessellated displacement using a runtime virtual texture. It uses two materials, one for the floor and another for a plane which has a decal component. Please note that the runtime virtual texture must have Displacement selected under Layout > Virtual Texture Content.

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Please let me know if this helps or if you have more questions.

Best regards,

Sam

9

thanks

10

No problem. I will close the case for now, but feel free to re-open it if you have any further questions.

Best,

Sam