Particle in POPs != position in POP sop.

[Wolfwood]

I'm running into a little trouble. Either I don't understand collisions in POPs or I don't understand collisions in POPs.

I'm importing a particle from POPs using the POPmerge sop. However the particle position in SOPs doesn't follow the particle's position in POPs.

In SOPs the particle avoids the moving geometry, but in POPs the particle hits the geometry object. (Which is suppose to be moving via CHOPs).

Examples:

This is the pic from POPs. The particle hits the box and bounces back. (Side note, why isn't this box transforming in POPs? Under the collision POP i have "Geometry moves with time" checked and "Ignore transfrom object" unchecked.)

In this one the box on the side IS moving and the particle misses it. Why isn't it following the particle in POPs?

The POPmerge SOP is using the last POP in the chain to retrieve the position. Which is also the SAME POP that is being displayed in the viewport.

To me it seems that there are TWO simulations taking place. One in SOPs and one in POPs. The SOPs one takes the moving geo. into account whereas the POPs simulation ignores the moving geo. But since I'm "merging" the Particle system into SOPs with the POPmerge SOP shouldn't there be just ONE simulation taking place?

jim.

[will]

first off, jim. this is cool.

next, change the chops driven movement from acting on the Y-axis at the object level to the box inside the right paddle. then you can see the geometry move in pops. when geo moves w/ time is on, the collision pop will use the paddles transforms in order to improve collision detection (it can be on or off and you will still see the paddle move). after doing that, the ball's movement appears to match in both places.

[Wolfwood]

Groovy.

If I had actually spent the same amount of time thinking about the process as I did trying to draw straight lines in the above pictures I might have figured it out.

Thanks Will.

jim.