How to cancel out camera motion from geometry motion?

[magneto]

Hi,

Basically I have some particles moving around within the camera which is also animated. I know by setting camera shutter to 0, camera motion blur is discarded.

Regardless of this, how can I remove the camera motion blur from the particles so that when I render them with motion blur (and camera motion blur), they will look like they discard camera motion blur? I want to do this for curiosity.

I assume I have to modify v.

 

Any ideas?

[Shinjipierre]

Here are a few ideas.

1. Well that will depend on your camera shutter but you could just force the camera not to have interpolation in your shutter time.
2. Other way would be to change the velocity attribute on the particles depending on camera space.
3. (My personal favorite, used on Ender's game) Parenting the object to the camera at render time.

[catchyid]

I guess, if you want to eliminate camera motion blur entirely you can simply go to Mantra Node -> Rendering -> uncheck "Allow Motion Blur". I have not tested how Mantra handles motion blur, but if does read the velocity vector and do the motion blur based on that then definitely you can remove v from particles before you render...

[magneto]

Thx guys. I need to modify particle velocities though as it's a different renderer we have to use and it doesn't have the option to remove camera motion blur only. It's all or nothing.

[bluealpaka]

hey Magneto, did you ever find a solution for this?

I've been trying to get it to work with a combination of moving the geometry to camera space and trail to get a velocity, but haven't really gotten anywhere...