Houdini Solvers Mutual Interaction

1A. Cloth – Pyro Interaction 
On default, pyro interacts withj cloth(if pyro solver connected first to merge node). However in this method,  pyro  do not colide but just affect as field force(left example) . In order to have proper colision, cloth obj should be imported with sop solver as colision source. (right example)

  1. importing velocity and density from source
  2. cloth simulation is imported with sop solver .
  3. Inside sopSolver: dop import  impors cloth object from curent dop network
  4. Inside sopSolver: imported cloth object converted to colision volume
  5. Source volume dop, imports cloth colision sdf


2A. RBD – Pyro Interaction 
In this example collision is introduced to sim by fluid source node in sop level. Density field is pushed by velocity of collision and all voxels inside colision is set to zero. On left version collision does not have any velocity hence density can not be pushed out but eaten by  collision. On right one colision is introduced to sim by static solver wich seems slightly faster to calculate.sourceCOlision.gif

  1. velocity calculated for collision object via trail sop
  2. sdf from geometry is built and velocity added by fluid source sop. From container settings”collision” is selected.
  3. density and temperature introduce for source object by source volume dop.
  4. collision is introduced by source volume dop.


2B. RBD – Pyro Mutual Relationship  In this one, two way  interaction between pyro and rbd is achieved by field force. In this method, force applied to rbd objects by generated by pyro solver. Colision is enabled by first connecting rbd than pyro solvers.

  1. import ground static object
  2. import rbd fractured objects
  3. field force for importing velocity. This node is fed by fetch data for importing vel from pyro object
  4. surcing fluid density and velocity



  • 1A. Cloth – Pyro Interaction
  • 2A. RBD – Pyro Interaction
  • 2B. RBD – Pyro Mutual Relationship

This post will continue with fallowing matrix (“pending”ones);

Top row represents effectors, leftcolumn represents affected ones. If both condition met simulation can be mutually interacted one.


4 thoughts on “Houdini Solvers Mutual Interaction

  1. Your really did some awesome research! Thank You very much for sharing Your knowledge.

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