Attaching child nodes/objects to an Object3D in three.js
three.js
Solution
You should be able to simply attach the spinnning sprites to using the add() function:
//create an empty 'container'/Object3D
var spinningSprites = new Object3D();
//add elements to it:
for(var i = 0 ; i < numSprites; i++) spinningSprites.add(yourParticleObjectInstsance);
//lastly add the whole container to the loaded model:
youLoadedModel.add(spinningSprites);
The above is an example, you would proably use different variable names, etc., but the idea is simple: use add().
Problem
I'm loading an .obj file into a Object3D object. That's working well and I can see it on the screen. However, I would like to create the impression of spinning sprites (fireflies, lightning globes, that sort of thing) at certain points above the object. I've been looking over the three.js documentation on sprites and other things, and am very impressed with the capabilities. But I need a little help on how to create a standalone sprite 'globe' as it were, with sprites flying about in their own local coordinate system, then moving that standalone 'globe' to a point above the obj file. Could someone help me get started with this? (I guess it comes down to, how do you position one object relative to another in threejs?)