Draw effects on the HUD

I’m trying to figure out how to draw normal 3D effects on the HUD for my gamemode, but its confusing me.
I KNOW it’s possible, I’ve seen it before but I can’t remember where.

Right now I’m trying to draw the effect in a cam.Start2D() block but I cant tell what to feed to SetOrigin to have it on the screen.

Does anyone know how to do this?