Particles from points that generate over time?

[charleyc]

I have a set of points that are part of a flaking effect using Spring. At a certain point (based off the distance from rest) I want the points to become particles and have them in a POP network where I can do whatever I need. I saw an earlier post about this that showed two methods for doing this, one involved pre-caching the points and the other was to use a DOP network (the one I preferred). Both seemed work when my points are all there at the start frame. However, I need them to come in once the distance threshold is met. If I use a simulation start frame for each frame ($F) i get particles created off all points at each frame, even if they had already generated a point. Basically I want a point to only become one particle. Also, once i get particles inside the DOP network, the forces and collisions inside the POP Solver dont seem to work. I am hoping this is the simplest way to go about this effect. Alternatively I would try to create a 'life' for my points lasting only a frame or less, so that I can simply read them into a POP Network source at each frame and they would only spawn at each frame. Any help would be greatly appreciated.

Thanks

Chalrey

pop_Disitegrate_002.hipnc

[JuriBryan]

here you are.

I always use a vop sop with a small time shift going into the second input. If you look at the inputs for the cache node you can see that its linked to the time shift.

So when you shift the second input of the vop 5 frames the particles will stay for 5 frames after they pass the threshold, and if you shift it by one the stay for one frame and so on.

Then I would use a simple pop network... no need for the dop network... at least at this point.

But anyways... here is the file with everything working.

pop_Disitegrate_002.hipnc

Hope that helps.

Cheers,

Juri

[charleyc]

Thanks Juri. That is a useful way to achieve my alternate method. However, it is still generating multiple particles for each input point. I was hoping there was a fairly straight forward approach to passing points straight into a POP network.

Thanks again

[JuriBryan]

okay I took a nother look at the file I created...

It seams as though the problem lays with gradient that is created by the first vop that you use to calculate the distance to the rest position.

If you lay down a group after that node and group all point with $CR==1 and then colour all points black and all points in the new group white.

Then use the vop sop/timeshift method in my file (make sure the time shift is set to $F-1) and then delete all points not with $CR==0.

The problem before was that my vop is checking for every value <0 that mean that a point that is slowly getting white will stay for more then one frame.

With this way I got 10356 points in the end of the particle sim.... to be honest I have no clue where the hell those 356 points come from.

Maybe someone with a more in depth knowledge can help us there.

For now I simply told the pop network that it can't have more points then you scatter on the pieces in the first place.

That way you have the 10000 points and no point more.

Here is the new file with everything working... besides the extra points:)

pop_Disitegrate_002.hipnc

Cheers,

Juri