Forums Technical Discussion Adding forces to a DOP object programmatically? [[SOLVED]]

Adding forces to a DOP object programmatically? [[SOLVED]]

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tshead
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Gang:

I’m trying to add a large number of point forces to a RBD object, and would rather do it programmatically than with a bunch of Point Force DOPs … it looks like the Script Solver might be what I’m looking for, but I haven’t gotten it to work yet … any examples floating around? Or is there a better way to tackle this? I considered a VOP Force DOP, but it looks like I’d have to convert my point forces into separate force and torque vectors myself, which I was hoping to avoid. Any thoughts?

Thanks in advance,
Tim
Edited by tshead - Dec. 29, 2023 23:54:45
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tamte
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not considering custom VOP/VEX solutions

if you are limited to DOP forces (oldschool RBDs) you can for example use Magnet Force DOP, which can use metaball field, so you can use metaballs copied to your force points

if you can also use POP forces (Bullet) there is similar POP Metaball Force
Edited by tamte - Dec. 28, 2023 03:10:38
Tomas Slancik
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Method Studios, NY
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tshead
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Thanks for the suggestions, I’ll take a look!

Cheers,
Tim
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tshead
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Although I didn’t end up going with the Magnet Force DOP or the POP Metaball Force, those were excellent suggestions that taught me quite a bit. In the end, I was able to get the Script Solver working - all that was missing was to wire it and the Bullet solver I’ve been using into a Multiple Solver.

Cheers,
Tim
Edited by tshead - Dec. 30, 2023 22:22:16
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cncverkstad
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Just if someone need that ex in Pic + You can Find ex In Houdini Help Files.. 


def solveForObjects(solver_data, new_dop_objects, existing_dop_objects, time, timestep):
    # RBD
    for obj in new_dop_objects:
        # RBD_Solver
        # Geometry OBJ
        with obj.editableGeometry("Geometry") as geo:
            //set file
            # Position, t
            Position = obj.createSubData("Position","RBD_State")
            Position.options().setField("t",hou.Vector3(obj.objid(),0,0))
            Position.options().setField("computecom",1)
            Position.options().setField("computemass",0)
            Position.options().setField("inertialtensorstiffness",1)
            # Gravity
            obj.createSubData("Forces/Gravity","SIM_ForceGravity")
            PhysicalParms=obj.createSubData("PhysicalParms","SIM_PhysicalParms")
            PhysicalParms.options().setField("bounce",1.0)
            # Colliders
            colliders=obj.createSubData("Colliders","SIM_ColliderLabel")
    # Geo OBj
            if False:
                objsim=obj.simulation()
                # Obj
               

        # no colide
            else:
                objsim = obj.simulation()

                
               
    for obj in existing_dop_objects:
            # 
            rbdstate=obj.findSubData("Position")
            t=hou.Vector3(rbdstate.options().field("t"))
            forcedata=obj.findSubData("Forces/Gravity")
            forcedata.options().setField("force",t.normalized()*-0.6)
            vel=hou.Vector3(rbdstate.options().field("vel"))
            vel=min(2,vel.length())*vel.normalized()
            rbdstate.options().setField("vel",vel)
            angvel=hou.Vector3(rbdstate.options().field("angvel"))
            angvel[2]=hou.hmath.clamp(angvel[2],-180,180)
            rbdstate.options().setField("angvel", angvel)

Attachments:
script.jpg (74.2 KB)

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