Form Sphere from Particles

Development Rendering
1

Hey guys n gals, so I am trying to create a firework effect, and I want the particles to leave from a center axis all at the same speed in all directions. It seems simple enough, but I can’t figure this out for my life, haha. So this is the problem, and the second part is what I want:

initialVelocity.jpg
initialVelocity.jpg512×963 94.9 KB

Any ideas? Thanks again all :slight_smile:

2

What you’ve drawn in the second image looks more like a ring than a sphere, but if you actually mean a sphere, this is how you can do it, starting from a new particle asset.

  1. On the spawn node, set Rate to: distribution: float constant, and the constant value to 0.
  2. On the spawn node, burst area, click the + button to add an item to the burst list. Set the count to the max number of particles, and the min count to the minimum number (or -1 if you want it to be a constant number of particles)
  3. Delete the Initial Velocity node.
  4. Add a Velocity Cone node.
  5. In the velocity cone node, in Angle, Set Distribution to Distribution Float Uniform, and the Max value to 360.
  6. In the velocity cone node, in Velocity, set Distribution to Distribution Float Constant, and the constant value to how fast you want the particles to start moving.
    (note, you can also set the distribution to Distribution Float Uniform, and set the min/max values close together to get a little variation on initial speed.

You probably want to also add an Acceleration node, and add a constant acceleration in -z to represent gravity.

All done :slight_smile:

3

hey oofnish, thanks so much for your help! Now that you mention it, I guess I am looking for both effects (sphere as well as ring), but what you’ve written has gotten me a lot closer than I’ve ever gotten to what I want. Hmm, so is getting the “ring” effect rather than sphere effect just a matter of playing with the velocity cone? If so I can’t seem to get it at first attempt, but I’ll keep trying, tricky stuff haha! Any ideas?

4

For a ring, in the velocity cone node, in Angle, set the max AND min value to 0.5. for more fun, set the lifetime value to 8 and the velocity cone->distribution constant to 25, and the velocity cone direction to <0.0, 1.0, 0.0>. Hypnotizing!

Also, I discovered that the angle distribution is not in degrees – seems to be ratio of something. So a min of 0 and max of 1 will give you a sphere also. Any matched distribution min/max will create a ring, but it will seem to “travel” along the normal unless it’s at 0.5. The travel makes a good effect too – for the hypnotizing effect, set both values to 0.1 instead of 0.5, for instance.

5

for a sphere you can also use the “sphere” module under the location tab which has a velocity value as well. you can get a ring with that as well by unchecking the corresponding axis pairs (pos and neg Y for example), but the ring will be oriented in world space and not orient itself towards the camera.
depending on your intended use that may be okay but if not you might have to rotate the particle system towards the camera via blueprint.

6

Amazing! Yup this gives me exactly what I need. Thanks so much oofnish, you’re a life saver my friend. I owe you lunch xD

Also, thanks sschroeder, yes the sphere module does create a sphere, but my issue was getting rid of the particles inside of the sphere or circle shape. oofnish’s trick seems to resolve this very nicely xD

7

You can check ‘Use Surface Only’ in the Sphere module, and they’ll only emit from the outer-most radius of the sphere, not on the inside of it.