Brushes or Actors for level design?

Hey guys. I’m a complete newbie at Unreal Engine 4 (never done any game design before) and I’m pretty used to working with Hammer World Editor. I became very adept at using Hammer, and one big thing from Hammer is that you used brushes to create the maps. Every floor, ground, wall, and landscape was made of brushes. I see that in Unreal, there are both brushes and actors that seem to be pretty much the same, such as the cubes and spheres for both. What is the difference between the two, when do you use one instead of the other, and which one do you use for level design (specifically making houses, buildings, etc.)? Thanks!

Don’t use brushes, the tools don’t offer much and BSP is bad for performance. Only use brushes to block out the level with the plan that you will replace them later with high detail static meshes.

Thanks. What do you mean by only use brushes to block out the level?

Blocking out means putting the coarse geometry in the level.
Walls, etc. Once you have set that up and tweaked wall heights and placement (where should be a wall or a staircase), then you replace that with meshes.
the advantage of Brushes in that stage is that you can easily make wall longer or taller or change the step count on a staircase.
If you are then happy with the overall look (rooms not too small, not too big, corridors are wideenough)… then you replace that geometry with “real” meshes.

Oh, alright. Thanks!

Here’s a good link to give you an idea: Blocking Out Levels - So Epic blocked out the level first to see where the were going to placed everything/ get dimensions of everything!

Oh, I see. It seems it would be quite inefficient to build the whole map with brushes then replace each brush with a mesh one by one. Is this how that’s actually done or is there a better way?

Well, that depends on how you use the brushes to make the level and how you plan to break your final geometry down into modular meshes.
While you can make two rooms, connected by a doorway with just three brushes, you woulnt want to make both rooms or even one of them as one single mesh.
If you also use several “standard” lengths for walls, etc, you will not end up with so many different meshes.
In this map, https://forums.unrealengine/showthread.php?73637-A-little-FPS-level&highlight=little+fps+level I used about 700 brushes to block out and then combined them to 80 meshes to make that level…
Also Blueprint can help you a lot in procedural mesh placement. Not everything has to be set by hand…

It always depends on your map and how the final meshes will look like -> for simple stuff like basic walls you can just add a bsp + convert it (but keep in mind that you probably still have to create a lightmap for it), but for the rest I personally would always just create them in a 3d tool and then place it (and probably modify + reimport it)