Hiya All
I am fairly new to houdini and due to political resons…soon to be resolved….I am using vers 6
We are trying to render very fast moving objects.
The question I am asking is that if an object moves very fast in an arc in front of the camera then mantra seems to interpolate the motion blur in a linear fashion between shutter open and shutter closed ..Does mantra have a setting where you can set subframe samples? so we can achieve a smooth arc..
The sample scene provided has a sphere moving quickly in an arc in front of the cam…the motion blur is a straight line…not what you would expect
Any help would be gratefully accepted
Oh yes like all converts Houdini ROCKS!!!!
Ta in advance
:shock:

Short answer is Nope, Mantra does not have multi-segment (subframe) motion blur.

Happily, it's relatively easy to work around this. Houdini _does_ have the ability to render on subframes, simply by entering an increment of .1 (or whatever is appropriate). Then, composite the results together to get the subframe blur.

Trickiest part is setting up the Comp to reconstruct it without too much pain. Probably you'd want to make an OTL (were those available in Houdini 6? I think so…) that wraps it up for you.

Please see attached for an example of rendering and then loading it back in. I don't have access to anything other than H8, so hopefully this will work )

Oh yeah, make sure any animation has subframe data! If you use $F in an expression, replace it with $FF (floating point frame number). Keyframes generally always have subframe data so that's not a problem.

Cheers,

Peter B

Ta Pete
I will give this a try when I am not being worked too hard…
:wink: