Metaball Sample Script

Description:

The following example shows a sample Metaball script using the Parray particle system.

Can Be Used With:

Should be used in a Script_Operator.

Effect:

In the Proceed handler, a new Mesh object is created with a vertex at each particle. Then, a PArray classical particle system is created and used to generate a metaball mesh out of all vertices of the supplied mesh. Now, using a Mesher compound object, a snapshot of the metaball is made and used as the shape of the first particle.

EXAMPLE

   --The ChannelsUsed handler defines the channels
   --to be made available to the script.
   --For the list of all channels, see
   --Interface: MaxscriptParticleContainer
   --The parameter pCont passed to the handler
   --contains the Particle Container the script is applied to
   on ChannelsUsed pCont do
   (
   pCont.usePosition = true
   pCont.useTime = true
   pCont.useSpeed = true
   pCont.useShape = true
   )

   --The Init handler is called on initialization.
   --It is not used in this case.
   on Init pCont do
   (
   )

   on Proceed pCont do
   (
   --Get the start and end times
   t1 = pCont.getTimeStart() as float
   t2 = pCont.getTimeEnd() as float

   --As long as there are particles 
   if (pCont.NumParticles() > 0) then
   (
   --Disable screen redraws to keep speed up
   with redraw off
   (
   -- create an empty mesh
   nMesh = editable_mesh()
   -- Set the number of vertices and faces to the
   -- number of particles.
   nMesh.numVerts = pCont.NumParticles()
   nMesh.numFaces = pCont.NumParticles()
   --We will make a single vertex for each particle
   for i in 1 to pCont.NumParticles() do
   (
   -- Time for the particle to travel at this integration step
   timeStep = t2 - (pCont.getParticleTime(i) as float)
   -- Speed is added to foresee the particle position at the end
   -- of the integration step
   nMesh.verts[i] = pCont.getParticlePosition(i) + timeStep * pCont.getParticleSpeed(i)
   -- The face references the same vertex 3 times!
   nMesh.faces[i] = [i,i,i]
   )

   -- create PArray with particles on vertices of the mesh
   a = PArray()
   a.speed = 0
   a.formation = 2-- at all vertices
   a.quantityMethod = 1--use Total
   a.Total_Number = 1--just initializing
   a.viewPercent = 100
   a.Emitter_Start = 0f
   a.Emitter_Stop = 0f
   a.subsampleCreationTime =off
   a.Display_Until = 2000f
   a.life = 2000f
   a.Growth_Time = 0f
   a.Fade_Time = 0f
   a.particleType = 1--metaballs
   a.metaballAutoCoarsness =off
   a.metaballRenderCoarsness = 0.9
   a.metaballViewCoarsness = 0.9
   a.Metaparticle_Tension = 1.0
   a.size = 5
   a.Total_Number = pCont.NumParticles()--use particles count
   a.emitter = nMesh

   -- acquire the metaball mesh from the PArray
   mshr = mesher() --create a Mesher Compound object
   mshr.pick = a --get the PArray
   metaballMesh = snapshot mshr --make a snapshot of the Mesher
   delete a --delete the PArray
   delete #(mshr, nMesh) --delete the Mesher and our mesh

   -- speed is added to foresee the particle position at the end
   -- of the integration step
   timeStep = t2 - (pCont.getParticleTime(1) as float)
   spaceOffset = pCont.getParticlePosition(1) + timeStep * pCont.getParticleSpeed(1)
   -- adjust vertex location to center around the first particle
   for i in 1 to metaballMesh.verts.count do
   ( move metaballMesh.verts[i] (-spaceOffset) )
   --Create an empty mesh to assign to all particles
   emptyMesh = editable_mesh()
   --Assign the empty mesh to all particles.
   --This makes them invisible
   pCont.setShapeForAllParticles(emptyMesh.mesh)
   --First particle carries all the mesh data
   pCont.setParticleShape 1 metaballMesh.mesh
   --Delete the empty mesh and the snapshot
   delete #(emptyMesh, metaballMesh)
   ) 
   )
   )

   --The Release handler is used to do cleanup work.
   --Not used in this case.
   on Release pCont do
   (

   )