Billboarding with mulitmesh

Question

How would billboarding be achieved using multimesh? Am I able to set the mesh to be a sprite3D or would I need to write a shader?

Edit: I should probably have given my question a bit more context (although I have come up with a solution which I will describe in an answer below). Trying to render fairly large forests in my open world game - currently using multimesh with some basic LOD to show or hide each forest (they are grouped together in multimeshes of a couple of hundred mesh instances. This is ok and runs fine but I've realised I don't actually need the detail of meshes for what I'm going for and that a billboard that's always facing the player should be perfectly fine even up close so I've decided I'm going to try replace my meshes with a textured quad

Answer 1

After doing some reading I discovered that there are apparently some performance problems with sprite3D at the moment? But also realised that this wasn't compatible from what I could see with multimesh. So instead I made a quadmesh and added a spatial material to it. Under flags I ticked transparent, under parameters I set billboard mode to Y-Billboard and ticked use Alpha Scissor, and then under albedo I set my texture to just a png which I got by rendering my tree model in blender with lighting etc within blender.

This gave the result of:

which is the effect I was after. I can do a bit more tweaking with the lighting as when I move the camera the lighting changes but for now it is fine and it runs at 60fps all day long. Hope that helps