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Roland Muller avatar image
Roland Muller asked ·

How to get transforms of a LightFilter?

Hi,

I'm trying to figure out how to get the transform matrix of a light filter.

I found I could get the matrix of the light that the filter is attached to with AiNodeGetMatrix(sg->light_filter->Lp, "matrix"). I am planning to do local overrides to Liu independent of the light transform tough so I'm wondering how to pass the transformation of the light filter itself into the shader? I found in Maya I cannot transform the blocker in the viewport at all and in Katana the transforms of the blocker won't get passed onto the .ass file.

Surely there's something I'm missing :)

Any help would be appreciated!

Thanks

lightingkatanafilters
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Pal Mezei avatar image
Pal Mezei answered ·

Hi @Roland Muller !


By default, light filters don't have a transformation matrix, so it's a parameter you have to create and make sure it's available along to the light filter. You can query it in node_update and store it in a local data struct.


I don't recommend using "AiNodeGetMatrix" in shader_evaluate, AiNodeGetXXX functions are generally too "slow" for shader evaluation(except AiNodeGetName). Why do you need the transformation of the light?

Cheers,

Pal.

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