VRayMtlWrapper as a mask

[Ferran_SDC]

Hi there!

New Vray user here!

I'm wondering if I can use VRayMtlWrapper information as a mask for "cutting" in either VRay Blend Mtl or VRay Standard Mtl (Opacity Map).
As the attached image shows, I'd like to use the black and white information (directional shadow info) of the Wrapper to mask things out.

Is that possible? I've tried many times connecting all of the Wrapper parameters via Connection Editor, without success.

I used to do that using the "outMatteOpacity" of a regular useBackground maya shader.

Thanks in advance!

[bigbossfr]

Hi,
You can set the alpha contrinution to -1 to get "the good" alpha

[Ferran_SDC]

Hi bigbossfr, yes your're right.

But what I'd like to do is to use this black&white of the wrapper info as a input to other shader. like a mask for the VRay Blend Mtl or Opacity Map in a VRay Standard material.
With that I can tweak for instance the shadow color/intensity or put other shaders behind the shadow.

In mr I usually do this connection with a "useBackground"----outMatteOpacity----->"RGBtoLuminance"----------outValue----->cutoutopacity"mia_material" (see image attached)

[bigbossfr]

Are you looking for the lightShadowFraction output attribute from lights ?

[Ferran_SDC]

I'm not sure. I'll look into it.

I want the direct raytraced shadow from a directional light information and use that as a mask.

[Ferran_SDC]

Trying to connect lightShadowFraction to BlendAmount (Blend material), no success...

Am I doing something wrong? Any other ideas?

Btw, has VRay something like mia_env blur?

[svetlozar.draganov]

It seams that lightShadowFraction works only with Maya Software Renderer - I had no success with Maya Hardware / MentalRay / Vray.
It is also not possible to pass the information from VRayMtlWrapper to a mask into VrayBlendMtl , what you could do is to bake the ground-plane texture and then use it as a mask.

[Ferran_SDC]

Thanks.
We're going to use Wrapper solution then.

Best.

[kristianturner85]

Hi guys,

This is something I struggled with when I first started using Vray. The mib_matte_shadow did this job in Mental Ray and could give you a luminence output you could use to control whatever you wanted. I found Baking with the VrayWrapper to be the best work around too. Maybe we could request a dedicated shadow shader in the Wishlist. The Wrapper does a lot of things well, allowing you to manually adjust different primary and secondary contributions, I just find that the shadow alpha option seems like a bit of an add-on.

all the best,

-K

[tashko.zashev]

Hi,

Maybe we could request a dedicated shadow shader in the Wishlist.

Will see if we can do something on that direction. Maybe an additional option or node..