Can I have 2 different rendering paths: deferred and forward in the same scene?

We want to have 2 cameras in the scene:

  1. perspective projection with deferred rendering path (normal camera)
  2. orthographic projection with forward rendering path (like mini-map camera)

So my question is, can these two different forwarding paths exist in the same scene, or this could cause performance problems?

It’s perfectly OK, it’s camera’s rendering, does not affect the composition of the scene. In fact, deferred camera does forward rendering for all but standard-lit objects (transparent, etc).

But I’d strongly recommend not to render the minimap simply as a topdown camera. I haven’t seen your scene, but you will most likely generate a lot of drawcalls that will barely fill a single pixel. Instead, I’d suggest you to render the minimap world only once, store that into a texture to be used as a gui background, and render objects on a minimap separately, ideally as simple dots? Create simple representations of your game objects for the minimap and update their positions.