when I insert the shaders into the HB Add Shade component, the runtime increases dramatically; very very long (in heavy projects only). But when I insert them into the HB model directly, the runtime is taken correctly with reasonable time. Is this a bug or are the shades discounted?
From your screenshot, it looks like you are assigning all of the shades to all of the rooms of the model, thereby duplicating the shades for each and every rooms. So that is why the simulation it taking so long to run. I would just assign the shades to the model rather than the rooms. I would only assign them to the rooms if you are willing to work with data trees to separate the shades that should be assigned to each room.