I have mesh which is map for my game. I want to split it into many objects (squares). I tried bisect tool but it’d take too long. I also tried some boolean options and i think that’s the way. I hope this picture will help you understand what i mean https://imgur.com/E2o6tgk Thanks for the help
Welcome to BA 
Is the map for your game made out of square faces? If so, this will be extremely simple. If not, you’re going to run into problems very quickly. As you cut up the faces into a grid- which is fairly simple to do, as you’ve mentioned, a few Booleans will do it very easily- you are going to have faces along the edges of the cuts that are n-gons. N-gons don’t work with the majority of game engines, so you’ll have to either triangulate all the faces, or triangulate just the n-gons. Either way, your underlying topology will be seriously damaged.
Does it matter if your topology is damaged? It depends, honestly. If you want any kind of deformation, it matters a whole lot. Also, long skinny triangles both don’t shade well and increase the time required for raytracing significantly, so if your topology gets cut up too badly, you’ll get shading artifacts and your FPS will drop in your game engine.
I would personally try and retopologize my map to be perfect quads/squares before cutting it up, if you haven’t already. If that’s not worth the time and hassle, you don’t have to. Either way, the Boolean method will work pretty well. Just note that you may have n-gons, which will have to be triangulated, and you need to be careful to avoid long skinny triangles
Can you explain me how can I cut it into a grid?
Can someone help me? I know I have to use boolean but can someone explain me step by step?
The bisect tool might be the thing…
https://docs.blender.org/manual/en/2.80/modeling/meshes/editing/subdividing/bisect.html
also there’s good old “P” >> separate selection
I tried bisect tool but it takes too long. Also separating selection won’t work because my mesh isn’t in squares. I’d like to use boolean to do it automatically, i just don’t know how
Booleans are pretty easy, but they can be messy. You add the modifier, select the ‘cutter’ from the field within the modifier panel, and then select the mode you want. I think “difference” would be the one you want but don’t quote me on that.
Hi there,
As @joseph mentioned, if the topology is quad-based, like a subdivided plain, then you can simply cut it up, basically Ctrl - P, break parts out by selection.
If, for some reason the topology won’t support it, a workaround is to create a new plain, and simply apply the material onto that, and that one you could subdivide and separate. I hope I understand the problem correctly