Can I use a background object while retaining alpha?

[Rev]

Hi there,

I'm using Octane 2.24 with Cinema R16

When I render an animation, objects with motion blur have a white fringe around them due to the environment being white. Using a backgrouind objects negates the fringe, but it also kills my alpha layer (turns it black). In a compositing program I have to 'ignore' alpha to get my image back.

Any ideas on getting a clean Alpha?

[Rev]

Seems that if I uncheck 'Straight matte' in the C4D output setting it fixes the problem.

[Rev]

Hmm the problem is back, and this time unchecking straight alpha seems to make no difference. The renderer is returning frames that are completely transparent still when the background object is added with an image.

[Studiolocal]

latching onto this thread. similar problem - rendering an animated character with motionblur i like to render an image sequence of the tracked live action plate so that the blurred areas will contain the right colour pixels when composting the renders together in Nuke. What is the right workflow to achieve this in Octane ? thanks