Hello, was just wondering if anyone has encountered this problem / whether it is a bug or just the way Houdini GL works.

Using the standard Principled Shader as a way to preview textures in the viewport for a project I'm currently working on - In total there are about 10 objects with full 2K textures with roughness, albedo and occlusion maps - none of these seem to be causing any performance difference using High Quality Lighting.

As soon as I apply a normal map to a material, geometry loading performance drops suddenly - loading a frame or updating the geometry which contains the normal map takes about 10x longer than without a normal map.

Once it loads, the performance in the viewport is about the same. Performance monitor assigns this calculation time to Other - any idea what might be causing this?

That's expected. Normal maps require tangents on the geometry. If the geometry has no tangents, then using normal maps will require generating tangents for display.

jsmack
That's expected. Normal maps require tangents on the geometry. If the geometry has no tangents, then using normal maps will require generating tangents for display.

Thank you for the answer!! Pre-generating the tangents made everything run pretty smooth again

yeah, the missing tangent performance hit is also heavily impacting the bone deform node if the geo has uvs. I my scenes I see that pre calculating the tangents makes it go from around 7fps to 30+fps.

And this isn't really obvious anywhere this happens, no warnings anywhere. I stumbled across it one time in some random internet post once.