POP Replicate By Velocity/Magnitude

[gramx]

Hi

I have a simple pop network with a popreplicate node to leave trails behind my particles. What I am trying to do is hook up the popreplicate node so that it emits more particle for fast moving particles and less for slow moving particles. Any help would be appreciated!

Thanks

Graham

[johner]

You can use the Emit from Attribute parameter on POP Replicate, although that does mean you have to create an attribute specifically for emission. With a POP VOP or Wrangle first create an attribute named "emit" or whatever that is just a mapping of speed to a 0-1 probability range, which should allow you to control the emission probability for every source particle.

Edited December 1, 2013 by johner

[gramx]

Thanks for the quick response I have been looking at Emit from Attribute parameter on the POP Replicate, but I am having problems creating the attribute, I have tried to set an attribute inside a POP VOP but it doesn't seem to do anything. Looking at the help it says the attribute must already exist. I'm not sure where I can create it.

[gramx]

Ahh, I managed to add the attribute to the source geometry! cheers

[gui]

if it still helps...

replicate.hip

[gramx]

Hi, I have added an emit attribute to the POP Replicate but I am finding this is not giving me the result I am after. If I put a low value in then some of the particles emit trails and some do not, If I put a High value in then then they all emit. I am trying to control all the initial particles so that if they are not moving they do not emit a trail and when they start moving they emit a trail based on there velocity. Similar to the birth by distance in 3dsmax PFlow.

[gramx]

Thanks for the example, I am getting an error on the merge saying a mis-match of attributes on the input was detected, and the replicated particles emit from the origin rather then leaving trails.

Edited December 1, 2013 by gramx

[johner]

See attached for what I was describing. The non-moving particles with emit=0 aren't replicated,while the moving ones stream out replicated particles. You could even add a hard cutoff for replication by enabling the Group parameter on POPReplicate and putting @emit>0.5 or something.

replicate_by_attrib.hip

[gramx]

Thanks johner, your example is really helpful

[eyoon]

See attached for what I was describing. The non-moving particles with emit=0 aren't replicated,while the moving ones stream out replicated particles. You could even add a hard cutoff for replication by enabling the Group parameter on POPReplicate and putting @emit>0.5 or something.

 

Thanks Johner, useful example !

 

How can I fit range of velocity like mapping speed to emit attribute in POP VOP ? (or other node)