paritcle delete base ID / whitewater source

[behappy]

Hello guys,

 

I work whitewater for splash.

I made a whitewater source particle.

I want high velocity pariticle delete.

So I made a high velocity group made.

However, The pariticle are removed from the group while slower speeds.

For example is parabolic movement.

But If I want to continue to maintain, including once in the group based on the ID.

I try it use sop solver. but point count changes does not work.

Is there any way what?

 

Many thanks,

 

Hyungi Jeon.

Edited April 16, 2016 by behappy

[djiki]

You can use POP SPEED LIMIT or POP DRAG node inside Whitewater_sim network to limit speed of your particles during simulation. If you want to remove particles from already cached simulation then inside Whitewater_import node put one Delete node SOP. Connect output from AttributeWrangle node to input of your delete node and output of your delete node to second input of VolumeRasterizeParticles node. In delete node set entity: points, operation: Delete by expression,  Filter expression: length(@v.x,@v.y,@v.z)>5

That will remove all particles from cached simulation with velocity greater than 5 and only in frames where velocity is greater than 5. If velocity decrease, particles will reappear.

If you don't want reappearing then:

1. put Solver node before your delete node

2. Inside Solver network create integer point attribute (AttributeCreate node and connect its input to first input of your solver), name attribute  VelocityReached and in value edit box type:  length(@v.x,@v.y,@v.z)>5

3. Create new integer point attribute (AttributeCreate node and connect its input to previous attributecreate node), name it DoDelete and in value edit box type: if($PT>=npoints("../Prev_Frame"),$VELOCITYREACHED, $VELOCITYREACHED || point("../Prev_Frame",$PT,"DoDelete",0))

4. Change expression in your delete node to: point("../solver1",$PT,"DoDelete",0)

That will prevent reappearance. VelocityReached attribute will change according to current velocity but DoDelete attribute once it becomes TRUE (first time velocity threshold is reached) it will stay TRUE forever.