random spin to particles/packed rigid bodies

stolen from a Toadstorm reply somewhere...

axis might be more finessed than just setting to z as shown.. Same goes for the angle, which I've brute forced to -90 times. Anyway, this will give a bit of spin to your packed rigid bodies

vector axis = set(0,0,1); // the random axis attribute you created

float angle = -90*fit01(rand(@ptnum), -1, 1); // change this to whatever range, in radians

vector4 q = quaternion(angle, axis);

v@w = qconvert(q);

spinning particles/points/rbds

I made a previous post about spinning particles with "w" and Pop Torque.... Walter uses this & it seems much simpler (?). In your DOP network, create a Pop Spin node & in the VEXpression space type:

spinspeed = 100*(fit01(rand(@id),chf("min"),chf("max")));
axis = sample_direction_uniform(rand(@id));

Spinspeed is measured in degrees per second
Axis specifies the axis of each point you're spinning. The sample_direction_uniform() function returns a normalised vector. So here, we have a completely randomised rotation axis. Not bad.

random rotation with POPs

To get random rotation with POP particles, add a point wrangle at SOP level with a more specific version of the following code-

v@w=rand(x-value,y-value,z-value);

Then in the dop network, add a POP-torque node and set the amount to zero, so that it takes the initial "w" value. "w" is angular velocity..all according to keikaku.