renderOrder property
Where this node's meshes draw within their pass, lowest first. Draws sort by it before anything else: opaque ones before their state and depth sort, translucent ones before their back-to-front sort. Use it to pin the order of overlapping translucent surfaces that depth sorting gets wrong (a thing seen through glass, or parts of one object). The default 0 leaves ordering to the renderer. Not inherited by children.
Implementation
// TODO(render-order-fscene): carry it in the .fscene document so authored
// scenes and the editor can set it.
double renderOrder = 0.0;