VRay_Velocity

[rfellers]

I've been messing around with VRay_Velocity and RSMB today and came across an issue... I set up simple scene using a linear color workflow with static plane in the background, a box moving horizontally, a sphere moving vertically, and a cylinder moving diagonally. I added a VRay_Velocity render element, set the max velocity scale to 2048 (recommended by ReVision for floating-point images) and rendered it out as a .vrimg which I converted to individual .exr. I load it all up in combustion with RSMB, set the max displacement to 2048 - the result applies a motion blur to everything, including the static background! There is more blur applied to moving elements, but somewhere along the way the rsmb plugin is not recognizing a static pixel correctly (probably shifting all the other pixels as well). I've looked into shifting the gamma, trying different things with the LUT, etc., but just can't figure it out. Any one else have this problem and/or a solution?

[vlado]

What does the velocity element look like? Is the camera moving?

Best regard,
Vlado

[rfellers]

The camera is not moving. Here is a link to the color and velocity channel of one frame (VelocityTest.zip)...

ftp://ftp.ryanfellers.com/

[vlado]

Hm, I have to try and reproduce this here.

Best regards,
Vlado

[rfellers]

I must have deleted the original max file I was testing, so I recreated it and posted it on my ftp if would like to take a look at it. There is a max 2008 file, a Combustion 4 file, and a zip containing the .exr (generated from the .vrimg out of max).

ftp://ftp.ryanfellers.com/

[rfellers]

I think I figured it out. It was a gamma/colorspace issue. When converting from the vrimg, I was using the -srgb switch. I tried it again without that switch, then in combustion I applied a gamma of .454 to the velocity channel before using it in the RSMP plugin. Works fine now. Is combustion wrong to not be interpreting the gamma correctly on its own?