All objets in the scene are instances of objects in the content manager, regardless of the plataform, to don’t mix up with unreal instance materials, Instance material is a material with modificated variables, soo count like a draw call.
Anatomy of Drawcalls
Draw = paint Calls = task
Drawcalls have the task to paint material in the screen, they need a task for each material
Soo If you have two trees with two material and one rock when one material:
Paint task
task 1 = Paint the first material in tree one
task 2 = Paint the second material in tree one
task 3 = Paint the first material in tree two
Task 4 = Paint the second material in tree two
task 5 = Paint the Rock first material
Total tasks 5 = Draw calls 5
Of course as say Rastar the engines can have tricks to combine meshes and reduce draw calls. But i don’t know if work in unreal and in some cases the consume of gpu is worst that the drawcalls. This happen to us in the last game for psvita that i work.