Hey there @guitou80! It’s definitely going to depend on how much draw is happening on the surrounding environment. Those tris are decent baseline estimations for a low end environment , but depending on the rest of the game and how lower end platforms you’re targeting. For PC a max of 500,000 tris at range is not a problem without some insane shaders.
I’d recommend if possible to stress test early and get your benchmarks as soon as you have a high poly mesh for the cars.
Oh no by no means anywhere near the limit or even an estimate of exactly how many you can put together, I was using your math from the zoomed out perspective of the cars (LOD3) is where it’d be the most taxing as long as LOD0 is Really close. We can slap a couple million triangles in a scene depending on the computer and shaders, there’s so many factors that an exact number range would be disingenuous. Mesh instancing makes it far lighter as well if need be, so every tri isn’t really equal in that regard.
To add, if you’re working with Nanite the poly count becomes mostly negligible down the line but won’t be useful for systems not able to run DX12 and Shader model 6.6.