[Bf-python] RenderEngine API - fractional frame

[Nicholas Yue]

> I just thought - Perhaps have you got blender interla's full scene
> antialiasing switched on? Perhaps there's a bug in which it will set off an
> external render multiple times if that option is on. It should really be
> ignored for external renderers and jsut let hte external renderer exporter
> handle all motion blur data export itself, but I'm wondering if there's in
> fact something wrong here...

I have re-run the test turning OFF anti-aliasing.
Same observation.

Probably what you gather from the above (it should be ignored for
external renderer....bug)

Regards