I’ve been doing some testing on texture LODs lately. I wanted to know if there was a difference between LOD Bias and Max Texture Size.
Answer: NO!
They do exactly the same thing, but in a different manner. Max Texture Size is a fixed size. LOD Bias is a relative size.
Max Texture Size won’t affect textures that are already equal or smaller size. But LOD Bias will affect all textures when you do a bulk operation.
Next step was to see if LOD Bias applied an offset to the LOD used on screen. I wanted to know if it just lobbed off the highest resolutions or if it applied an offset and kept using a coarser resolution than normal at all distances.
Answer: No offset. Uses exact same resolution as any other texture.
That means if you use a LOD Bias, it just cuts off the highest resolutions. The math to pick the resolution to display remains the same. So if you use a texture with LOD Bias and one without, they will both use identical resolutions except when up close because one texture has those resolutions missing.
To test this, I used a texture that had different colors and text indicating the resolution on each LOD. IOW, each LOD had a different image. And I confirmed that the exact same resolution is used regardless of any of these setting if the resolution is available.
Here is the file if you want to see what texture resolution is being used.
When you import it, ensure Mip Gen Settings is set to LeaveExistingMips
Each LOD has a different image. Here is LOD 3 and 4 to give you an idea.
If you ever wanted to know for sure what resolution was being use with all the different settings and upscalers, this image will tell you.
The original was made by someone else. But it only went up to 512 even though it was claimed to go up to 1024. I fixed it and updated it to go up to 4k. You can see the original here: