Hello Guys, I have some issue with @orient values for particles on POP context after plugging POP torque / POP spin.

When I plug one of this nodes my copied geo on particles start look like on ex_v01

Before sim I randomize v@N for random look instanced geo after coping to points.

When I bypass POP drag / torque all look fine randomized, because I think use Normal for adjust orientation.

How I can randomize orientation value at the beginning of simulation particles?

Thanks advance!

Can't you just set randomized values on your source points, and have your particles inherit those attributes?

Construct a quaternion vector4 orient attribute on your source points then feed that in to your POP simulation.

Orientation will be kept through the simulation. Orient will override all other methods of orientation when you place instances or copies through the Copy to points SOP.

Note that the instance pieces will no longer be updated by the velocity attribute and will remain in the same orient position unless you affect it directly.



There are a few POP type DOPs that affect the orient attribute to make life a lot of fun:

POP Touque DOP (applies torque modifying the orient attribute at the current timestep)

POP Drag Spin DOP (Uses W torque at the current timestep and affects orient to dampen the rotational force)

POP Local Force (applies forces to the particle using orient as frame of reference)

POP Lookat DOP (affect orient to force copied/instance geometry to look at a specific position in space)

POP Spin DOP (creates/uses W torque but expects orient to be present as spin local frame of reference)

POP Spin By Volumes DOP (same as POP Spin DOP but uses volumes to affect W torque)

POP VOP DOP (affect quaternion v4 orient attribute how ever you wish with VOPs)

POP Wrangle DOP (affect quaternion v4 orient attribute how ever you wish with VEX snippet code)

jeff
Construct a quaternion vector4 orient attribute on your source points then feed that in to your POP simulation.

Orientation will be kept through the simulation. Orient will override all other methods of orientation when you place instances or copies through the Copy to points SOP.

Note that the instance pieces will no longer be updated by the velocity attribute and will remain in the same orient position unless you affect it directly.



There are a few POP type DOPs that affect the orient attribute to make life a lot of fun:

POP Touque DOP (applies torque modifying the orient attribute at the current timestep)

POP Drag Spin DOP (Uses W torque at the current timestep and affects orient to dampen the rotational force)

POP Local Force (applies forces to the particle using orient as frame of reference)

POP Lookat DOP (affect orient to force copied/instance geometry to look at a specific position in space)

POP Spin DOP (creates/uses W torque but expects orient to be present as spin local frame of reference)

POP Spin By Volumes DOP (same as POP Spin DOP but uses volumes to affect W torque)

POP VOP DOP (affect quaternion v4 orient attribute how ever you wish with VOPs)

POP Wrangle DOP (affect quaternion v4 orient attribute how ever you wish with VEX snippet code)

Thanks Jeff!

you can as well use Attribute Randomize to randomize orient

Attrib Name: orient
Distribution: Direction or Orientation
Dimensions: 4
you can play with cone angle and seed etc.

tamte
Tomas Slancik

Yes, thank you, orient is very interesting attr, I need explore more about this.