Override Mtl - but keep opacity of original mtl

[Neilg]

Says it all on the tin - I want to use a fully black override material but keep the opacity of the original materials intact.

It's for volumetric passes - I do them with a black override and layer it in post, but if there are any trees then it takes a fair bit longer to set up.
Would come in useful for rendering out depth/velocity passes after the original is done too.


I dont know how hard this would be to do, or if it's possible, but I would use it all the time

[vlado]

Well, it would be kind of similar where you would override, but keep the original bump map. I think it can be done, just need to think about it a bit.

Best regards,
Vlado

[windowlicker]

Bumping this old thread.

I have recently done a few jobs where I've rendered scenes with a white or black base material (env.fog, gi, ao passes etc). The problem is always the windows - you still want the light to shine through. I often model windows as a single poly object and detaching the glass from the windows just so I can exclude them from the material override is a real b*tch. Especially when working on huge models, imported from Revit or Autocad.

The most simple solution I can see would be to be able to exclude from Override mtl based on material, and not on object as it is now. Would it be possible? (Also if it is inside a multi-mat?)

And sort of related: Would it be able to make separate checkboxes for Reflection and Refraction in the Global Switches menu?

[vlado]

The most simple solution I can see would be to be able to exclude from Override mtl based on material, and not on object as it is now. Would it be possible? (Also if it is inside a multi-mat?)

Unfortunately no. 3ds Max has no concept of include/exclude for materials.

And sort of related: Would it be able to make separate checkboxes for Reflection and Refraction in the Global Switches menu?

It can be added, but I'm curious when you would need it?

Best regards,
Vlado

[windowlicker]

Too bad. I kinda feared it was the reason for it. I guess the easiest way is to replace all materials but the glass with a black or white material in the material editor before render, and not using the global override at all. (Maybe it can be scripted...)

I need it when I have a lot of refractive layers and I need the refracted rays to pass through them all. Then you can still keep the reflections at a lower value to save render time. It's not often it happens, but it does from time to time. Atleast for me.

[Neilg]

It can be added, but I'm curious when you would need it?

I would use this. For my GI i'd leave refraction on, but switch reflections off for IR/LC passes. At the moment I hide the glass objects.
It would be useful for doing a seperate glass pass too - we render ours seperately and reassemble it in post and it's be nice to simply switch off refraction to get the pass rather than save another copy of the scene and change the materials.

Not a major deal in any way, but I would use it for sure.

[Dave_Wortley]

You can easily easily do this with a maxscript.

Simply go through all the materials in the scene
Create a Black Material
If there is an opacity map on the original assign the opacity map to the new material
replaceinstances originalmat newMat


That's it! (well gets more complicated with VrayBlendMtls, Multisubs, but still do-able with a simple recursive function)

[TKT]

bit of a necro bump here but while googling this is what came up, rather than anything newer. Did this ever get done? I know corona can ignore glass and displacement in its override but I cant find anything similar in VRays override?
It's nice to have a building being worked on in another file but you can xref it in, apply override and tell it to ignore transparency for things like glass or preserve opacity for leaves on vegetation to still allow light through

[vlado]

We are currently working on this for the next update of V-Ray 5.

Best regards,
Vlado

[Morne]

We are currently working on this for the next update of V-Ray 5.

Best regards,
Vlado

Was this implemented yet?

[Vizioen]

Was this implemented yet?

Yeah, it is.

[Morne]

Yeah, it is.

Could you give me some pointers what I should be looking at please? Been staring at vraymtl and also at the render dialog override settings, but nothing obvious jump out at me...

[Vizioen]

Clicking this button will open options preserving, bump, refraction, opacity, self-illumination and preserving lightmtl.

[Morne]

Ah thanks. The text label from Next is now turned into a sneaky button in 5, nice!

[Matador]

Hi
anything similar to this on Vray for Maya?
thanks