Random particle size with VrayProxy and Alembic

[sliverfx]

Hello guys

I'm testing alembic particles import from Houdini into Vray 3.00.03 with VrayProxy. And it's a great feature !

It's also really interesting to have an access to Particle Width Multiplier

I'm wondering if is it possible to render particles with a random scale ? to have width variation ?
Which attributes is used from Houdini to render point scale ?

Thank you very much

[vlado]

We are reading the particle sizes from the "width" channel as per the Alembic specification. However Houdini typically ignores almost everything from that specification If you manage to make it put the widths in the correct place (although I'm somewhat doubtful you can do that) we will render them.

Beyond that, we can probably try to recognize channels called "radius" or "width" or something like that... what is that channel typically called in Houdini? Also, can you post such an Alembic file here or send it to support@chaosgroup.com ?

Best regards,
Vlado

[sliverfx]

Hi Vlado,

Thank you for your quick reply.

In Houdini the particle scale attribute is called : pscale (I will try to convert pscale as "width" or "radius" before alembic export)

Here a link to download basic a spray of few particles (50 frames) if you want to check it : https://www.dropbox.com/s/h0nxwoo7q3...embic.abc?dl=0

[sliverfx]

Good news !

The solution to affect a random value to particles and to renamme in Houdini channel "pscale" to "width" works perfectly !
It works only with "width" channel not "radius" channel.



I'm going to try how to export also particle color.

Thanks for your advice Vlado.

[l_yuriki]

Hi sliverfx!
Can u post please how do u rename in Houdini channel "pscale" to "width"?

Sorry I find solution by myself
I used node "attribute rename" before "ROP Alembic Output" to rename "pscale" to "width".

[sliverfx]

Voila Attribute rename works perfectly

[BrianW]

Can I ask the specifics of getting Houdini to write out the alembic? It only exports the collision objects and not the particles itself when I try it.
Any tips would be greatly appreciated!