particle cannon

how would i make particles attracted to a point? like in a particle cannon?


have a mesh with gravity set to it.

how do i do this?

It’s pretty simple:
1)Add an empty and position it where you want the force of attraction/repultion to be (You can make any object be a partical attractor, but empties don’t render so I like them).
2)Under the Object Buttons (F7), click on the [Partical Interaction] tab.
3)I think what you want is a force field, but you can also try a vortex.
4)A positive strength means it will attract particles, a negative strength will repel
5)A Fall-Off greater than 1 will act more like gravity- The closer you are to the source of gravity, the stronger the effect
6)Now you need to recalculate the particle trajectories by selecting your particle emitter, going to the Effects tab, and press the tan [RecalcAll] button.

Play your animation and repeat steps 4-6 as neccessary.

Fall-Off is always a positive value, so I have to assume you meant: “A value of 2 will act more like gravity. The distance affect the effect by a power of two”.


my biggest problem now is that once the particles touch the center of the object they start moving away from it %|

Try setting 2 forcefields right next to eachother… The particles should bounce back and forth…

Just add a mesh at the center and make it a collision object for the particles system. Same panel as the attractors.


now, im not really sure how to do that either…(sorry that i suck so bad :expressionless: ) would you use the deflection option or what?

Yup, you’d use the Deflection option for that. Be sure the mesh with the deflection option is on the same layer as the particles system. In your case, I’d also set Damping to 1.0 (the rest can stay on the default values).


Two topics that I think would make great video tutorials have been mentioned in this thread. Particles and empties. That’s right … the versatile, humble empty … so many varied uses.

I hope some of our great video tut writers read this (GreyBeard). :slight_smile:

Two topics that I think would make great video tutorials

no video tutorials
my connection is to slow it takes 15 minutes to download one megabyte

or have video ones and written ones for slow connections

ive been considering making some image tutorials for a while, using Wink. they would be alot smaller then videos. looks like particles will be one of the tutorials.

ill start making them when my holidays start (about a week or two.)

(Sorry for getting off topic with my last post … and here too :frowning: )

Well, I like video tutorials. I especially like the way GreyBeard approches his tutorial subjects. I understand that it might be difficult for some to download 68MB avi files, but they are being posted at and from what I understand they can be downloaded using a bittorrent client. I have not used this mechnism (I can usually download at an average of 140KB/sec), but it’s supposed to make it much easier to download large files.

they still move away…

make a cube as the point where you want them to stop, and re calc the normals inside, then make it deflect them. that way they will enter the cube and get stuck inside.

negative time IPO ==> no need for fancy force field foolery. :wink:

whoa whoa whoa…negative time ipo might help…step by step please…

Well, I assume you know how to make the effect in time-reverse, i.e. little particles coming out from the emitter instead of being sucked in. so make your little particle spewer. Suppose it starts emitting at t = 0, stops emitting at t = 50, and has a particle lifetime of 50.

Now, go to the IPO window and find the ‘Time’ label on the right side (make sure you are looking at the object IPO and not Material, world, etc.) you want to map t = 0 to t’ = 50, and t = 50 to t’ = 0, so place two points at (0, 50), and (50, 0) and select linear extrapolation so you get a line with a negative slope. Now, run your animation, and in the first frame, you have bunch of particles, and they will move inwards until nothing is there at t = 50. Just play around with the numbers to get the right timing.