Help with fields and rotation - another approach?

Hello, I’m still trying to get the ‘spinning wheel of smoke’ effect.

In this image the cube is orbiting the big sphere. (Sphere has constant rotation, cube is just child of an offset null).

I want to have ‘smoke’ emit from the cube, so I added Primitive Emitter and tried driving it’s position with the cube. The more astute among you already see the problem; the cube ITSELF isn’t really moving (in local space anyway), since’ its offset to Null position and left alone. It only LOOKS like it is moving because the parent sphere is rotating. Make sense?

I’ve tried parenting, channel mapping, even ‘Transofrm Modifier Apply Mode’ = World …nada.

Any idea how to get this Primitive Emitter to follow the cube (or just move in a circular pattern (dont want to do spline-follow))?

Thoughts on getting it to work as intended are greatly appreciated!

I’d suggest you upload a project file or a screen shot of the nodegraph - would help a lot with figuring out what is potentially at fault.

– Ryan

Thanks Ryan, here’s the whole thing (screenshot).
It’s dirt simple. Imagine the moon is child of earth, earth spins and moon goes around. In this case, i want the moon to be a Field Primitive Emitter (labeled ‘MOON Primitive’ in this image).

I have tried many methods of ‘parenting’, MOON/EARTH (here, null is mapping PosX/PosY/PosZ to moon).

any help appreciated, thanks!

ps,. any theory what i’m doing wrong w/ Skylight that it wont light the sphere? (Root has Deferred checked)

Jason Kaehler_Field Rotation.dfx (1.4 MB)

Hey Jason,

Couple of things here

  • There is a difference between the “Skybox” and the “Sky Light” (Sky box is just the Spherical image, the Sky Light is the actual lighting.)

  • You have the primitive emitter output hooked back into the input of the field root ( the output is basically for parenting, I can’t imagine any scenario where you would use the output of the primitive emitter in this way)

  • You are using a pink procedural Null instead of the Geometry Null ( I tested it with a pink Null and it still works so this tip is just for best practices)

  • Adding a null between the 3d Object and hooking the output into the “Transform Modifier” input of the primitive emitter should work. See the attached project file to compare your settings to mine.

I hope this helps!


1 Like

@BeerO Absolutely helps, infact solved it perfectly! Thanks!