Can't render motion blur for ice instance shape?

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jerry7
Posts: 45
Joined: 22 May 2010, 01:43

Can't render motion blur for ice instance shape?

Post by jerry7 » 26 Dec 2013, 05:01

Can't render motion blur for ice instance shape with mental ray?

NNois
Posts: 754
Joined: 09 Jun 2009, 18:33

Re: Can't render motion blur for ice instance shape?

Post by NNois » 26 Dec 2013, 09:38

hi jerry,
the best you can have with Mr in this case would be velocity blur and rotational blur but no deformation blur.

this is even more complicated if you are animating your instances in an unsimulated ice tree, because softimage does not calculate theses values for you, see my tread here https://www.si-community.com/forum/v ... =15&t=4513 for example... In the last post i've posted a compound who calculate for you these values and render motion blur for mental ray.

If you want deformation motion blur... :
There is hope ! you can use emTopolizer2 http://www.mootzoid.com/plugin/emtopolizer2 he takes your point cloud and output for you One polymesh deforming over time, i haven't tested the last version but this is awesome emTopolizer takes now the instance time parameter !!

-> In this case in Mr you can just tick the deform motion blur and you're good ;-) . If you can't afford this plugin, you can always use the default softimage compounds but you will just have one instance shape, or if you use the graham compounds, the setup is a little difficult, but you won't have the shape instance time... see here for some info https://www.si-community.com/forum/v ... =15&t=1579 or https://www.si-community.com/forum/v ... =19&t=3588

jerry7
Posts: 45
Joined: 22 May 2010, 01:43

Re: Can't render motion blur for ice instance shape?

Post by jerry7 » 09 Jan 2014, 08:53

hi NNois,
Thanks for relply. I just use position moton blur.
I use softimage 2014 sp2, and I found the problem. I use "Set Instance Geometry" compound , there is no motion blur。if i edit the compound and delete the "Self.ShapeInstanceTime", Motion blur is worked.

Is it a bug?

NNois
Posts: 754
Joined: 09 Jun 2009, 18:33

Re: Can't render motion blur for ice instance shape?

Post by NNois » 09 Jan 2014, 09:00

hi,
is the point cloud moving the instances, or is your instances moving from themselves ?
and is it a particle simulation or an unsimulated point cloud ?

jerry7
Posts: 45
Joined: 22 May 2010, 01:43

Re: Can't render motion blur for ice instance shape?

Post by jerry7 » 09 Jan 2014, 10:19

hi, the point cloud moving the instances. I just make a basic emission, and only use a sphere as instance, and checked motion blur.

NNois
Posts: 754
Joined: 09 Jun 2009, 18:33

Re: Can't render motion blur for ice instance shape?

Post by NNois » 09 Jan 2014, 15:27

did you cache the simulation ? (environement -> cache on playback)

jerry7
Posts: 45
Joined: 22 May 2010, 01:43

Re: Can't render motion blur for ice instance shape?

Post by jerry7 » 10 Jan 2014, 02:00

Not cached. I found if i delete ShapeInstanceTime, mblur appeared.
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NNois
Posts: 754
Joined: 09 Jun 2009, 18:33

Re: Can't render motion blur for ice instance shape?

Post by NNois » 10 Jan 2014, 11:16

yearrr i can repro that here.

if i try to explain it a bit.
first you can't really use set instance geometry on an "emit" node because "set instance geometry" is used to update the "animation time of instances" BUT an execute on emit port is evaluated ony once when the particle is created.
So use an "instance shape" node... and in this case the motion blur works ;-)

If you want to keept the original animation of your instance, use "control instance animation" or "set instance geometry" but not on the execute emitter ports.
Please note that doing that remove motion blur on your instances, this is explained here and you have to relly on mentalray standins (or emtopolizer i gess) http://download.autodesk.com/global/doc ... d30e381841