[fv]

Hi,
I was wondering when a material has 2 layers, and each Layer has only 1 BSDF. What is the difference if you set the weight for 1 Layer at 50 or set the BSDF weight inside that Layer at for instance 50.

If you do the Layer at 50 I understand this Layer will reduce 50% in its presence in relation to the other Layers. If there is only 1 Layer it will become half transparent. But if inside that Layer there is only 1 BSDF with a weight of 50% what happens ? Am I right to say that with 1 Layer and 1 BSDF component the weight of the BSDF component does not matter ?

Francois

[JDHill]

Within a single Layer, the BSDF weights will be normalized to 100.0. So, having a single BSDF @ 50.0 is no different than having it set to 100.0; it will only make a difference once there is another BSDF in the same Layer, in which case they will be mixed according to their respective Weights. Layer Opacity will be applied to the Layer as a whole, regardless of how many BSDFs it contains.

So yes, you are correct when you say that BSDF Weight makes no difference when there is only one BSDF in a Layer. Does that help to clarify things?

[fv]

Perfect, that was what I wanted to know.

I wonder sometimes, downloading gallery materials and looking at materials exported out of SU, why you would have one layer with 3 components, or have 3 layers each with 1 component.
I also understand that if you set a BSDF within a Layer to 0 and the other at 60 the one at 60 will be normalized to 100 leaving the BSDF 0 at 0.

Actually the layer system is great and works very well but at times it complicates the settings of a material. For instance a reflectivity Layer set at 50 with an BSDF at 75 and its roughness value at 25. Before you know it you have a mxm that is too messed up to edit.
Francois

[JDHill]

Keep in mind that many times when you are downloading an MXM gallery material, that it is a 1.x material, and that the SDK has to do a translation; it tries to do that as well as possible, but since the material model is so (infinitely, actually) flexible, it is not possible to guarantee that all translations will be perfect. The determination of whether it shows up as 1 Layer with 3 BSDFs vs. 3 Layers with 1 BSDF each should generally depend on whether the original material used Additive blending mode or not. If it used Normal blending, then it should be translated as 1 Layer with 3 BSDFs; those 3 BSDFs were being normalized using their Weights in the original 1.x material, so they will do the same in the translated material. Conversely, if the material used Additive mode, then it must be split up into three Layers, each with one BSFD, and using Additive blending between Layers.

I hope that helps to explain some of what you might see when 1.x materials are brought into a 2.x scene.