cg.earlyworm with a post showing how to camera map multiple projections onto one object in Nuke using the MergeMat Node, which allowys you to composite all your Projecte3D Nodes togehter before applying them to an object.

cg.earlyworm notes that Camera projection is pretty straight forward when it comes to mapping one projection onto one object. It becomes less straight forward when you want to map multiple projections onto one object, and this is where the MergeMat Node comes in.

Check out the post for how to Camera Map Multiple Projections onto one Object in Nuke Using the MergeMat Node here.