i have < 400 uv faces and walking became slow
and there are < 200 uv faces, walking good
do i need connect multiple meshes into one mesh?
@PavelBoytchev @Lawrence3DPK may you advice me?
Depends a lot on what you mean by “slow” (GPU vs CPU).
Also depends entirely on how your “walking” is implemented.
It’s likely you do a lot of raycasts, and casting against more triangles takes more time. You might want to have a look at either:
- nav mesh
- a spatial index to accelerate ray casts, like a BVH or and Octree
@Usnul thanks 
I restored location that I created
it is working fast
The issue was in cpu, i created many meshes from scratch in memory and threejs page became slow
It is hard to give advice when there is a lot of unknown things. Maybe the first thing to check is to make sure that these uv faces (whatever you mean by this term) are causing the issue. In the snapshots I also see a lot of models – the black structures at each vertex. Maybe their number is also related to the slowdown?
Generally, slowness comes from ineffective data or ineffective algorithms. When the number of elements is small, such ineffectiveness do not show up, but as things gets more massive, they become dominant. I think this is what you experience now.
Merging geometries is useful when the slowness is caused by the number of drawing calls. If your issue is something different, then merging will not help significantly.