As I’m primarily a programmer I’m still experimenting with 3D modeling. I have complete understanding of how 3D models work (having done a module on it during my degree) however, I ask, how many vertices are too many for a model?
Clearly the more you have the harder the hit your machine will take on performance so is there a way of optimising models so that you don’t go overboard? For this engine higher amounts of vertices are obviously allowed.
It always depends on your size of the level, denisty of placed meshes and which kind of model it is.
Optimise:
-use lods ?v=17pcyPVplEc
-use culling volumes
Just a note: In games the triangle count is crucial
Thanks a bunch, that tutorial is very useful! It’s great to know Unreal has LOD features built in, it can be painful trying to code them in yourself 
Drawcalls are much worse than triangle or vertex count. And dynamic lighting rendering, shadow rendering, material complexity, depth complexity, etc.
In a high end engine like this that are dozens of factors that have an impact on performance, and many of those have a much bigger impact than a models vertex and triangle count. There is no single number, and not even a range of numbers that will answer your question. It all depends greatly.
Indeed, what Hourences said.
Keep the count as low as possible without alterting the shape too much. And keep an eye upon not to waste polys unnecessary. I just got some model back from a friend who made a cinema chair with a cupholder, where that cupholder had almost 1/3rd of the triangles of the entire model. A waste of ressources, especially given the many instances that be used in the scene.
However in the end you have to measure the entire scene and see what takes up most performance, which often can be a lot of other things as well. For example bad particle effects that use up CPU power without even being visible. Whenever you create something, keep the drawcalls in mind and see how you can make it so, that details are used only when the player really sees them or they’re vital for the scene.