VrayBlendMtl Multimatte and Reflections

[3ddesign]

I thought I'd share some testing I've been doing trying to get Multimatte layers from materials within a VrayBlendMtl and getting them to also show up in reflections. Here's the setup. A box with a VrayBlendMtl comprised of two materials seperated by a black and white map, and a mirror.



Using the AutoMultiMatte07 script from Sergey Pogosyan http://www.sergepogosyan.com/scripts/AutoMultiMatte/ I created a MultiMatte Render Element and together with PSD Manager 3.1 rendered the scene. The following is the result in Photoshop with one of the masks turned on. In order to get the mask to show up in the Mirror I had to select "All Channels" in the Affect Channels drop down box in the Reflection section of the Mirror material.




In order to get good antialiasing I had to select NONE in the Filtering section of the VrayBlendMtl, Blend Amount Map.



All seemed to work well until I added another Coat Material and Blend Map in my VrayBlendMtl.



A closeup shows how the edge of the mask has problems that I was never able to resolve. However, in my limited testing this kind of edge noise happened more often when i used round or oval shapes as the Blend Amount Map and was less of a problem when using rectangular shapes.



If I can solve the noisy matte issue this will be a technique I would use on every project.

Craig

[3ddesign]

I'm continuing to experiment with Multimatte Elements from VrayBlendMtls trying to eliminate the jagged edges and stray pixels. So far no luck. Does anyone have a clue what's going on?

[dans]

Maybe share the scene, so someone can have a quick look at it.

Daniel

[3ddesign]

OK, solved the jaggies and stray pixels: I was using a jpeg as my blend map. Using a tiff eliminated them.

The attached shows a Photoshop screenshot closeup of the render. The material is a VrayBlendMtl with four sub materials deliniated with black and white maps. Another closeup shows the Photoshop screen with two PSD Manager layers turned on (black), one layer with a levels adjustment masked with the PSD Manager selection layer (White) and the Yellow text turned lavender again with an adjustment layer created from a PSD Manager selection layer.

As you can see in the second image there are some halo issues but for my purposes this is OK.



I'm excited that I can get the mattes to show up in a mirror but my next task is to see if I can get them to show behind glass, something I haven't been able to get to work yet.



EDIT: Dan, I'm going to play around with getting mattes behind glass to show up. If I can't get it to work I'll share the scene. Also, got to say, now that I've gotten this to work PSD Manager is going to save me a TON of time.

[3ddesign]

Hot dog! Mattes behind glass works. The script by Sergey Pogosyan was the difference. I was just setting up the MultiMatte Element wrong. The mask even picks up the refraction from the glass (arrow). This is cool.

[ajroane]

This would be really helpful. Unfortunately, Sergey's script only works with Vray 2.0.

[dans]

Hot dog! Mattes behind glass works. The script by Sergey Pogosyan was the difference. I was just setting up the MultiMatte Element wrong. The mask even picks up the refraction from the glass (arrow). This is cool.

What was your mistake in MultiMatte?

Daniel

[3ddesign]

I'm not sure since I didn't save progress files, but I think it was that I didn't check isMATID (and don't even know what it does).

[vlado]

I'm not sure since I didn't save progress files, but I think it was that I didn't check isMATID (and don't even know what it does).

It causes the MultiMatte element to work with material IDs, rather than object IDs.

Best regards,
Vlado