In workshop mode, there is a "Settlement" bar in the upper right that shows how "full" your settlement is. If the bar is full, you can't place any more objects in that settlement.
My question, then, is if we know how this is calculated. Is it by the number of objects placed, the size of objects, or some other criteria? Does placing 100 large items, like walls or staircases, count the same as placing 100 small items, like light bulbs?
Also, does scrap contribute to this max limit? I know that Sanctuary, in particular, starts off with an abundance of the yellow-outlined items you can scrap. If these contribute to the max limit of objects in the settlement, it'd be a motivation to fully clean up the settlement as a first task.
Best Answer
The size budget is a polygon count designed to keep your frame rate steady by preventing you from building massive and overly complicated settlements. The size limit and current size used are actually attributes against the workbench in the settlement itself and differ between settlements.
This is calculated based on the number of objects in the settlement in combination with the size and complexity of the objects. More complex objects have a higher polygon count and as such use more of the budget. Scrap contributes to this limit so you could "fill" a settlement and then go around destroying all of the broken beds, cups, chairs, etc and have more budget available to build more.
These numbers can be changed using console commands on the PC on a per settlement basis, although it is not recommended.
To get/set the triangle count limit:
To get/set the draw call count limit:
Make sure you're looking at the workbench of the settlement when you use these commands.