Cineversity

Hello,

With the PSetData, one can adjust the local time of particles at birth, but is there a way of adjusting the local time of particles post birth, so that one could, for instance, have particles slow down, stop, and revert back into the emitter?

Thanks!

Jerome

Hi Jerome,

This would be a lot of data, as it might need to reverse all the influences to the particle, to the perhaps millions of particles. 
In other words, I have not idea if there would be a way with reversing the time alone.

If that would be needed for a project of mine, I would perhaps (depends of the requirements of the project) use the Tracer, and set the resulting spline to work.

I have attached another way of getting this effect, I guess you like to “re-engineer” it by yourself :o) ...if not, let me know.

My best wishes

Sassi

Image: how to get particles back from this set up, with a new Matrix

Sassi,

Ah!  Got it.  You bake the simulation in a MoGraph cache, then offset the playback.  What I don’t understand about the C4D offset is why a value of -89 at frame 0 and a value of 90 at frame 90.  Why isn’t it an offset value of 90 at frame 0 and 0 at frame 90?

Thank you.

Jerome

You’re welcome, Jerome.

(I did not set the numbers 100% correct:“89 vs 90” etc.  Whatever… :o)

Think of two rulers: two stick like objects. One is the recorded animation or cache (blue), one is the timeline (green).
The one that represents the timeline is considered fixed in its position (green). The second one, representing the cache (blue), is placed with its end to the start of first. Total length is twice of a single ruler.

On the end of the animation the second one (blue) has its start point at the end of the first (green). Total measurement of the set up, again twice of a single ruler.

I hope with the images and the scene file this becomes more clear.

To get that perhaps better across, open the attached file.

My assumption is that you think of the single frame in the cache that you would like to have, but the off-set is based of the “body of information” at the current time. So the blue one needs to be moved about its total length negative to have its end point to the start of the timeline. On the end of the timeline it needs to be moved of a positive value of the whole time to be placed with its start. With that it moves twice of its length.

All the best

Sassi

Got it.  The animation really helps sink it in for me.

Yes, my assumption was something more like time reversing in After Effects (Layer>Time>Time Reverse Layer), where the sequence of a layer is simply inverted.  This clarifies C4D’s approach immensely.

Thank you.

You’re welcome, Jerome.

In Ae you move inside of a single layer in your example, this is a different story. In Ae terms that would be moving the layer and changing the position in a sub-comp. Then it would be similar ;o).

All the best

Sassi