Motion Blur on an animated light

[joshyclouds]

Hi everyone,

I'm trying to render a scene where my lights change colour/intensity between frames. I was hoping to see these colour changes in the motion blur but when I try and render it the light just stays a constant colour/intensity even though I can see it changing when I scrub through in the viewport. Has anyone else managed to get something like this working before in mantra? 

I've set up a simple test scene here with one light animating around and changing colour & intensity.

Cheers!

MotionBlur.hiplc

[joshyclouds]

So I ended up finding a solution for this that worked for me, I thought I'd post it here in case anyone else runs into this problem.

I was told by sesi that a light only has it's color/intensity sampled once at the shutter open time in mantra, but you can sample geometry attributes over sub-frames if you add the parameter 'vm_segmentattrs' to your mantra node and list the attributes that you want to be sampled. So instead of using a light I used a bit of geometry and animated the Cd attribute which was plugged into an emission shader to get the effect I was after.

MotionBlur_2.hiplc

Edited May 12, 2018 by joshyclouds