Alot of instances or large models?

Okay, I am designing a large open scene, now I’ve got a small question, is there a difference between placing alot of instances of planks, scrap metal and wood logs for example to design a house and placing the planks and logs and everything in the model itself and placing it as a combined 1 instance in lagging.
Does many gameobject instances makes more lags than one gameobject instance which have the same count of polygons as the instances…

It sounds pretty silly but still might be important.

The bigger issue is if the objects have different materials.

If the materials are the same then Unity knows how to batch these objects so that they only take one draw call. Of course it’s slightly more optimized to just have one mesh though anyways. This does come with a side note that apparently the free version has rather limited batching abilities.

If the materials are different, it doesn’t matter if it’s one mesh or several. Anyways it’s going to eat as many draw calls as there are materials.

I suggest that you concentrate on minimizing the amount of materials you use.