HISM doesn't decrease draw calls, it increases it!

Hello, I’ve made two maps, In the first one, I created a massive building with only static meshes of building modular panels.
In the second map, I converted the static meshes into Hierarchical Instanced Static Mesh Components stored in a blueprint actor.

Result :

  • First map : 50 draw calls

  • Second map: 500 draw calls

for the same amount of panels, at the same point of view.
I’m very confused now, can someone explain me why using HISM is not reducing the amount of draw calls like it should?

I am working on the same question, created s imple scene with 5000 actors and rendered them as single actors, instance static mesh and hierarchical instanced static mesh.
In my tests the single actor version gives the same FPS as the HSIM. the simple instanced mesh version gives only half the framerate.
I am confused as to what this means as well
there is this tool on the marketplace (Instance Tool in Code Plugins - UE Marketplace) and the author stated in the description that since 4.22 UE has an “auto instance feature” which would explain the equality of single objets and HSIMS. Maybe creating HSIMs manually is no longer necessary.
I would also appreciate if somebody with knowledge about this could add an answer

HISMC seems to have lost it. The draw calls seem to be the same or more than the basic static meshes. ISMC has a lower draw call but i cant get it to LOD. Was using 4.25.0 for testing.

Confirming it. UE 4.27.2 increases draw calls. Tried to built a small scene with and without HISM, and suddenly scene without HISM “eats” less than the same scene, but with HISM-actor.