three.js: how to control rendering order

for threejs r70 and higher is renderDepth removed.

You can set

renderer.sortObjects = false;

and the objects will be rendered in the order they were added to the scene.

Alternatively, you can leave sortObjects as true, the default, and specify for each object a value for object.renderOrder.

For more detail, see Transparent objects in Threejs

Another thing you can do is use the approach described here: How to change the zOrder of object with Threejs?

three.js r.71