When using material attribute layers in a material layer setup, there is a potential discrepancy in the number of VT Lookups presented in the material instance's Platform Stats.
When the same texture sample is used to set multiple different elements (e.g. Metallic, Roughness, Occlusion) into a material attribute layer, the stats will count each use as one texture lookup. However, if it is instead connected directly to the material the number of lookups remain the same as the number of texture samples.
(Attachments refer to the attached images in the linked UDN case):
1. Enable virtual texture support in your unreal project
2. Create a material that uses Material Attributes and plug the node ''Material Attribute Layers'' into it.
3. Create a material Layer and set two texture sample in it, one for the base color and the one for an MRO (Metallic, roughness, Ambient Occlusion). Plug both into a ''Set material Attributes'' (Attachment #1)
4. Copy everything you did in the Material layer (both texture sample + ''set material attributes'')
5. In the material mentioned above, set your new Material layer into your ''Material Attribute Layers'' and paste what you copied directly into the material (Attachment #2)
6. Save you material and create a Material instance from it. In it, click on ''Platform Stats'' (Attachment #3)
7. If you have plugged your ''Material Attribute Layers'' in the material, you will see that the VT lookups show 4 VT textures (even though there are only 2 texture samples) and if you plugged what you pasted from the ML directly into the material, VT lookups will show 2 VT textures (Attachment #4).
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-230399 in the post.
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Component | UE - Rendering Architecture - Materials |
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Affects Versions | 5.4 |
Created | Nov 14, 2024 |
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Updated | Nov 14, 2024 |