It depends on what those meshes are… Things to remember:
Unreal has a lot of culling etc built in. Generally it’ll only render what it needs to render or what it’s been told to render however:
- If you have a large, single mesh that covers a large area (which I think you do looking at this:296689-then seeing just one pixel of any part of this mesh will cause it all to draw. The engine will not only draw the bit you see, it’ll draw the whole thing, so you might want to break your bit mesh into smaller chuncks (one per room or something)
- Hierarchial meshes are exactly the same as above, but it’ll attempt to draw many instances of that mesh in one go (i.e. 10 meshes can be drawn in one batch, which means 1 draw call rather than 10). This means that if you have a group of 10 instances and one pixel of any one of them is drawn, all 10 instances will then be fully drawn. That’s fine if your mesh is cheap, not so fine when it’s so high poly and complex so you need to decide what should and should not be instanced accordingly.
- Also on Hierarchial meshes. If you have 10 instances of a mesh, and that mesh has 1 material it’ll take 1 draw call. If you have 2 materials on that mesh it’ll now take 102 drawcalls (20). Have 10 and it takes 1010 draw calls (100). So, Hierarchial meshes are best used when you have a single material in the mesh.
- Use lodding where you can. Again, when you have a big, complex model like in the images you posted Lodding might not be possible unless you split your model up.
- Hierarchial LODs (HLODS) are great. They can be used to simplify meshes and materials, but they come at a memory cost and again, can only really be used at distance.