Performance penalty when using Max native Physical Material?

[zaar]

Hi!

Corona seems to fully support the Physical Material that is native to Max. Haven't checked all the features yet. But, is there any penalty in performance when using it?

Of course I prefer the Corona Material when ever I can, if just for easy of use. But there are situation where using only Max native material and maps might be necessary. Does anyone know if I would be looking at a severe performance hit? Or are we talking about a 1% increase or something like that?

[maru]

There is no penalty. The Autodesk Physical Mtl is internally parsed into a Corona Legacy Mtl.

[zaar]

Best news EVER!

Anything one should know about how transparency+depth and SSS gets translated to Corona Media Options?

[maru]

"Depth" under transparency - it looks like this setting is ignored.
Sub-surface Scattering with depth set to 0 - this seems to work like Corona's translucency (simulating SSS on an object with near-zero thickness).
Sub-surface Scattering with depth set to non-0 - this seems to work like Corona's SSS mode.

[zaar]

It's been a long day here, but I can't get metallness 1,0 to work.

I create a Physical Material and put metallness to 1,0, put it on a teapot, pick an HDRI. It's not metallic in Corona, but in Arnold and V-ray. Maybe this is logical because the CoronaLegacyMat didn't have metal, buuut maybe it could be mapped to the IOR in some clever way?

Any recommendation on how to make a metal with Physical Material so that it renders resonably the same in all three renderers?

[zaar]

Oh and thanks for the answers about the media options!

Seems I can up the IOR on the physical material without Arnold changing apperance much, but it starts to look metallic in Corona.

[zaar]

Oh, and there's three modes on the physical material. Classic Simple, Classic Advanced, Autodesk Standard Surface Compliant. I found it slightly differences when inputting the same values on classic simple and advanced. Any input on that? Does that choice affect the parsing in Corona in some way?

[maru]

Why exactly do you need to render the Autodesk Physical Mtl in Corona?

Metalness is only available in the Corona Physical Mtl. Corona Legacy Mtl does not have this option.

With the Corona Legacy Mtl, the proper way to get metal materials was cranking up IOR to higher values (~30 or more).

[zaar]

I want to be able to use Corona for high quality stills and animations as I think it’s the absolute best renderer for that. But I also need to bake textures and publish low poly assets as glTF/GLB. Or maybe I just want other users that use other renderers to render my assets. So I need to use v-ray or Arnold for that.

Is there any technical reason for not parsing the physical material to a Corona physical material? If metal doesn’t work I don’t think one can say that Corona supports the physical material properly yet.

[zaar]

V-ray renders metalness 1.0 on physical material identically as VrayMtl with metalness 1.0.

Max's physical material seems more a like the Corona Physical Material than the legacy material. Is there any specific reason for in not being parsed to a Cr Physical? Was the work done before the Cr Physical Mat was introduced?

I'm so longing for some sort of cross render/platform way of describing materials and maps. If just inside a "Chaos ecosystem". V-ray won't render the Corona Physical Material only the legacy one.

[maru]

I want to be able to use Corona for high quality stills and animations as I think it’s the absolute best renderer for that. But I also need to bake textures and publish low poly assets as glTF/GLB. Or maybe I just want other users that use other renderers to render my assets. So I need to use v-ray or Arnold for that.

Thanks, I get it now. This is indeed challenging. As far as I understand, you would either need to use one material that all the different software interprets in a similar way, or use some kind of converter to convert between the different formats.

Is there any technical reason for not parsing the physical material to a Corona physical material?

Was the work done before the Cr Physical Mat was introduced?

Yes, exactly this. This is not a very popular use case, so it simply hasn't been done yet.

I'm so longing for some sort of cross render/platform way of describing materials and maps. If just inside a "Chaos ecosystem". V-ray won't render the Corona Physical Material only the legacy one.

Yes, I agree cross-compatibility would be great. The V-Ray converter can convert Corona Physical Mtl: https://docs.chaos.com/display/VMAX/V-Ray+Scene+Converter
Perhaps this could be a solution for you?

[zaar]

Thanks, Marcin!

I submitted a feature request so my thoughts and wishes end up "in the system" so to speak :)

The converter is good as a one way workflow, but I didn't even try it as it's less flexible and no going back. I have two sets of materials (30+ for one product...) both in v-ray and in corona now, depending on if I need to bake or not. It's a huge pain! Probably bigger than moving to whole stills/anim production into v-ray. But v-ray is not as nice and quick to work and render in :(

There's got to be a lot of places that are doing some kind of design viz that soon will want to put all their high poly assets on the web too. "show the product in 3d" -style.

Is there any info you can share on what Chaos or Corona thinks of MaterialX? It seems like the promised land, but I'm yet to understand how it will actually work in the end.

[romullus]

Was the work done before the Cr Physical Mat was introduced?

Yes, exactly this. This is not a very popular use case, so it simply hasn't been done yet.

Here goes my vote. Better support for Max's physical material is something that would quite interested me for reasons similar to ones that's listed above.

[maru]

Request for parsing Autodesk Physical Mtl into Corona Physical Mtl logged.

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