Hey guys,

I'm hitting a mental road block trying to understand how to rotate a particle around its velocity axis with a POP Torque DOP. In the attached file I've set a force and defined an orient attribute with Z aligned to its velocity. On the POP Torque there's an option labeled “Axis Relative to Particle's Orientation.” The description of this option says, “The provided goal axis will be rotated into the particle's own reference frame. Thus a value of (0,1,0) will be up in the space of the particle rather than in world space.”

I figured enabeling this option would allow me to set the Axis parameter on POP Torque and it would look at the incoming orient attribute before determining the final rotation axis. However, when I feed in an orient attribute it doesn't even rotate at all.

In the file I've also included a separate setup (to the right) showing what I'm hoping to achieve with the POP Torque node.

Any insight would be appreciated!

JoshFoster
Hey guys,

I'm hitting a mental road block trying to understand how to rotate a particle around its velocity axis with a POP Torque DOP. In the attached file I've set a force and defined an orient attribute with Z aligned to its velocity. On the POP Torque there's an option labeled "Axis Relative to Particle's Orientation." The description of this option says, "The provided goal axis will be rotated into the particle's own reference frame. Thus a value of (0,1,0) will be up in the space of the particle rather than in world space."

I figured enabeling this option would allow me to set the Axis parameter on POP Torque and it would look at the incoming orient attribute before determining the final rotation axis. However, when I feed in an orient attribute it doesn't even rotate at all.

In the file I've also included a separate setup (to the right) showing what I'm hoping to achieve with the POP Torque node.

Any insight would be appreciated!

Hope this helps someone, but for me, I had to use a rotation matrix after the simulation. If you want just randomize it, you can set an attribute randomize (rot) and you will have the particles rotating.

JoshFoster
I figured enabeling this option would allow me to set the Axis parameter on POP Torque and it would look at the incoming orient attribute before determining the final rotation axis. However, when I feed in an orient attribute it doesn't even rotate at all.

In the file I've also included a separate setup (to the right) showing what I'm hoping to achieve with the POP Torque node.

just disable orient2 node or execute it only on just born group or just on first frame or before sim

since if it's executed every timestep before poptorque it will keep resetting orient to the same orient destroying what torque did