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export particle rotate channel

Posted: Fri Oct 06, 2017 5:40 pm
by Stefx
How to export particle cache rotate channel for Type - Granular with DY_Domain? (for later use with instanced objects)
I tried to activate rotate under Export: Particles cache rotate channel under Check options and in Export Central
I then get this error message.

"WARNING: The particle channel "rotation" for node DY_Domain01 has not been computed. Go to the "Particle Channels" panel and activate the option to compute this channel."

Is this a bug?

Because under Particle Channels in the DY_Domain - Domain menu there are only options to activate Vorticity and Normal.


Re: export particle rotate channel

Posted: Sun Oct 08, 2017 12:41 pm
by tsn
This really sounds like a bug. Or better: it seems as if the developers forgot to enable "rotation" by default or add a checkbox to calculate this channel on demand. I'll tell the RF developers about this issue.

Re: export particle rotate channel

Posted: Mon Oct 09, 2017 2:47 am
by Stefx

Re: export particle rotate channel

Posted: Mon Oct 09, 2017 12:21 pm
by tsn
Hey Stefx,

I've forwarded this issue to our developers and they explained me the meaning of the rotation and conform_tensor channels:

Rotation is only required with "Viscous", and "Viscoelastic" requires rotation and conform_tensor, esp. when you want to resume simulation with these materials. In this case, the channels should be activated to guarantee a correct behaviour. What's definitely wrong is the warning you got, because it's completely misleading: with granular or liquids the two channels are not necessary and have zero meaning.

Sorry for the wrong information in my first post, but the explanation of rotation and conform_tensor was new to me as well. So, the only "bug" is the warning.