VRay Proxy + velocity pass problem

[Shimakaze]

I'm having a rather serious issue with rendering out a velocity pass in a scene that uses a lot of VRay proxies for trees. If I change the scale of the proxies their velocity effect is scaled as well.
Here's a picture with scale untouched.
http://www.ascantica.com/stuff/velocity1.jpg
Here scale is set to 0,99
http://www.ascantica.com/stuff/velocity2.jpg
And here scale is set to 1,01
http://www.ascantica.com/stuff/velocity3.jpg
The more it's scaled the more dramatic the difference. In my scene the proxy object had a velocity value of over 1000 while the ground it was standing on and everything next to it was at around 15.

Oh and a related question. Any hope for opacity support for this and the Z-Depth channel?

[vlado]

Thanks for the pointer, will try to correct this.

As far as opacity is concerned, you are mostly interested in the case where an object is fully transparent so that you can see the z-depth/velocity of objects behind it, is that correct (like the opacity-mapped leaves of a tree)?

Best regards,
Vlado

[Shimakaze]

Exactly or for RPC people (Hate using them but the clients love them)

[pinpan71]

depth and velocity behind opacity maps and/or refractions would be great, vlado.
i don't use yet the vray channels but the rpf channel that i am used too. so that function in both cases would be perfect for me.

[vlado]

It works fine for the RPF channels; the RPF file stores information about all objects seen in a pixel, not just the front one, so no problem there.

Best regards,
Vlado

[andy_butler_7]

Possible solution

Hi all.

We've recently had the same problem with Vray proxies and their Velocity element values being massively different so when applying a motion blur using fusion the trees and people which were proxies don't appear correctly.

When you say the scale values are 0.99 and 1.01, I assume you scaled using the vray proxie spinner in the modifier tab? Not the Max Scale tool.

After reading your post Shimakaze I started to look in to it, this is what I found.

Click on one of your proxie objects and in the modifier tab check the scale value, under the path location for the file is set to 1.0. In my file scene units were in meters. The proxies were merged from a file which had units in millimeters so the proxies scale value was .0001. When I changed this value to 1.0 my tree scaled by 1000 times so I used the normal Scale tool in Max to scale it back down to the correct size.

When I re-rendered and had a look at the velocity pass the velocity for the tree was perfect and had similar values to the objects around it.

So in conclusion, make sure your Vray proxie, in the modifier tab, is set to 1 and scale your Teapot using the Max scale tool. If you ever have a lot of objects which you want a random scale to, like I do for my trees, you can use a Blur Script to scale them all in one go.

I hope that helps!

Butler.

[Shimakaze]

It works fine for the RPF channels; the RPF file stores information about all objects seen in a pixel, not just the front one, so no problem there.

Best regards,
Vlado

After lots of testing I still can not get this to work. Also, I don't particularly like RPF files so I'd still like to have those channels as render elements as well.
Edit: Speaking of which... Is there any chance of getting any extra options when saving to EXR rather then vrimg in the "raw image file" section? Things like adding those extra channels (if they aren't added as render elements) and pre-multiplying of the alpha and so on?