see attached hacked together over the last day or so from online examples of code I could find (and lots of reading the MDL manual!)
its not got any texture slots hooked in yet (working on it) but it does work reasonably well - the SSS parametrisation is a little weird right now until I can work out how to stop the volumetric side of it making things too dark - code is commented so open it up in a text editor for some inline notes
only really works in path trace mode and iray - its kind of busted in real time mode
this is cool, looking forward to playing with it!
only had a look at the code at the moment, but it would be nice to have a dedicated mode for thin walled geometry (leaves etc).
the ideas is sound but its a bit light on implementation - the github code is kinda half finished (or was the last time I looked at it)
this was more just for fun, since I as finding the inbuilt surfaces a little limiting and the arch cad stuff that seems to make up most of the MDL you can actually grab online is of limited interest to me personally beyond waht I can learn from deconstructing it
I’ll probably have an improved version of this that Ill shove up in the next few days, but I have to se if I can sort out a few issues with energy conservation - too many parameters make the shader darker right now - especially thee SSS, though the way I’m doing it here is sort clunky anyway (rendering a volume inside and essentially peering into that via a diffuse transmission bsdf - that seems to be pretty much the only way to do it with the stock function definitions but looking at GTC Nvidia have a much more sophisticated shader coming soon anyhoo :)
yep, agreed - there isn’t that much available easily for this sort of stuff. a link I found interesting is this one
at the bottom there is a free download to an mdl to visualize sss in substance via iray
however that might just be another rabbit hole to get lost in (as it seems to include additional substance specific functionality), but yeah - might not be worth the time for all the reasons you mentioned
just discovered this - seems to be a pretty complete implementation of Autodesk’s standard shader direct from the reference OSL
I noticed it essentially does the SSS the same way I’m doing it, but with fancier math :)
it has many of the same issues therefore on SSS (ie SSS albedo in no way matches the diffuse albedo and is much darker)
yeah I’m still planning on developing mine with tex slots - though I’m tempted to use the more advanced template I linked to as its much more complete and ‘correct’ in general
one thing I’ve discovered though is Create RTX does not seem to implement the correction term on various MDL BSDF’s that compensates for energy loss due to lack of multi scattering on microfacets (which affects practically ALL the available BSDFs) - so essentially all high roughness surfaces will have darker edges than they should - this issue tends to compound itself on layered shaders
The RTX Renderer talk from GTC is now on On-Demand channel and anyone can view them now. At the end is a preview for Digital Human rendering in Omniverse. More info to come in the coming months, in the meantime, check out the talk and take a look. There are a lot of great info about the RTX Renderer in this talk alone that is worth watching.
