Motion Blur makes object shrink

[OlaHaldor]

I'm about to model a steam locomotive, and before I set out on that task I wanted to test the rig to make rods and pistons move as they should.

The three wheels seem to lose some size over time.
I've activated MultiPass MB, and motion blur lenght is set to 50%
If I lower this to 10% it doesn't lose as much size, but I'm afraid that will kill the rest of the feel of motion elsewhere in the frame.

[OlaHaldor]

Just to flesh it out a little, I made a complete render for you to see.

[juanjgon]

I recommend don't use the multipass MB if possible. Now Octane has it's own native motion blur that should work fine for this kind of scenes.

Disable the multipass MB and try to use the native Octane motion blur. Set the "objects motion blur steps" parameter to at least 6 steps:
http://render.otoy.com/manuals/Lightwave3D/?page_id=404

The problem is that if the object rotates more than 180º in only one MB step, you are going to get artifacts in the MB rendering.

If you have problems with the Octanenative motion blur, let me know.

-Juanjo

[OlaHaldor]

Always something new to learn.

Thank you. Solved the issue right away.