Better defaults for AlSurface

[LudvikKoutny]

Hello,

since AlSurface has in my opinion significantly more usable SSS than VRayMTL, I tend to use it to most of the SSS materials these days. But since it defaults to roughness and Beckmann BRDF, it tends to take significantly more setup time to get the material done. It would be nice to have AlSurface defaulting to GGX and glossiness workflow, with option to always switch to Beckmann and roughness for those who are migrating materials from different renderers. No more invert nodes before roughness input

Alternatively, we could have AlSurface-based VrayFastSSS3, with just a single SSS lobe, reflection layer and minimalistic UI for basic SSS materials like fruits, food, marble, etc... and AlSurface would be niche for things like skin.

Or, just have SSS component of AlSurface available as one of the modes in VrayMTL SSS.

Thanks in advance.

[^Lele^]

You can quite easily write a scripted plugin shader for it, and through that either set the defaults you like (some want them as they are for portability, you see, with other software), or even add a rollout with your own presets.
The caveat would be that the plugin shader would then need to exists by the max which opens a file authored with it.But as long as you're doing things in-house, it should be the least of issues.
Shader encapsulation is a super nice, and not too difficult, exercise to get into Maxscript, i'd highly recommend it (there is a pretty much complete example in the docs, it's a case of copy/paste/change.).

[^Lele^]

So, here's a sample for you to play with.
Put the attached script in your startup folder (or if you just plan to look at it, run it.), run max, and find the shader called "Ludviks_VRayAlSurfaceMtl" (its category name may be odd. make sure you look hard for it.).
The original AlShader's UI is left untouched, but a new rollout is now present, "Presets Manager".
The default selection from the rollout is applied on shader first creation, so it defaults to GGX. the "Default" preset is there just to illustrate what changes.

Feel free to augment it as you see fit, it's meant to be a starting point.

Rough to gloss conversion will need to happen in code, but i don't see that as a showstopper (it costs one output map with "invert" ticked. Literally four clicks. Times at most two layers.).

Either way, have fun.

[LudvikKoutny]

Thank you! I will give it a shot asap.