Possible to mip bias specific streamed virtual textures?

Development Rendering
, ,
1

Hi!

We have a case where we would like to set a lower limit to specific streamed virtual textures.

Either by controlling LODBias or MinLODSize or anything really.

The textures are used for opacity and we never want to see the lowest Mip levels.

Is that in any way possible?

Best

Felix

2

Hello,

Thank you for reaching out.

I’ve been assigned this issue, and we will be looking into methods of biasing specific Virtual Textures for you.

3

Hello,

Based on your question and MinLODSize callout, I am assuming your intention is to stay on higher detail MIPs and not go down to lower detail MIPs when you say “we never want to see the lowest MIP levels”.

You can try using a negative MIP bias in the Material in the details panel of the Texture Sample expression.

Please let us know if this helps.

4

Hi again!

I did get it working now in a new material.

My previous testing material was just a bad one to use for debugging.

Thank you for all help :slight_smile:

Best

Felix

5

Hi!

That did not work for streaming virtual textures.

It does work for regular textures though.

6

Using Unreal Engine 5.5.1

What I have tried so far without success:

  • r.MipMapLODBias
  • On Material, any on the MipValueModes
  • On the texture asset
    • LOD Bias
    • Texture Group (both custom group and engine default group)

The only option left which I can think of and I would really like to avoid is to create my own custom MipMaps.

7

Hello,

We were able to get positive results testing with manual MIP level calculations in the Material, with a clamp. Do you have an example of your setup you could share, or how you are testing it? This might help us understand what part of your implementation is failing.

The guide for EPS Submissions: [Content removed]

Keep in mind that the texture will still be subject to the Virtual Texture streaming - if the Virtual Texture pools are full, it might be dropped to a lower MIP level to reduce the load on the pools. The solution to this is to increase the pool size, as long as you remain within your project’s memory budgets. You can also check if other Virtual Textures are consuming more of the pools than you desire, and bias them downwards.

Please let us know if this helps.

8

Hello,

Thank you for confirming it is now working.

Can we close your case? You can always re-open it if you find you need additional assistance for the same issue.

9

Yes you can close it.

Thank you again.