Motionblur samples problem

[gagui]

Hello, I am having an issue when increasing the geometry samples on some helicopter blades that rotate at high speed. If I leave the samples at 2, it looks as expected, but if I increase them to properly render the curved motion blur, the effect seems to break.
I am attaching some screenshots illustrating the problem.
Thank you.

[gagui]

Ok, I found the problem was the animation of the rotation in the blades was an expresion. If I change to keyframe animation it renders ok.

[viktor_angelov]

Hi gagui Thank you for sharing. Glad you managed to make it work.

Would you say that the Motion Blur did not work when the animation was lead by an expression?

[gagui]

Yes, It doesn't work if you raise the geometry samples for the motion blur when the animation is lead by an expression.

[bdancer]

> It doesn't work if you raise the geometry samples for the motion blur when the animation is lead by an expression.

Make sure your expression returns float value otherwise there is nothing to interpolate (e.g. use $FF not $F).