Hello busy bees

Lots of reading to do (especially on the other side), but at first glance, a few thoughts.
About terrain density
@liquido: in order to avoid angled faces, just set the shading to smooth and it will be kept in AC as well (in case this is what your concern is). Here is a picture - look at the red water pipe - the LEFT one has actually less polys than the RIGHT one.
About road meshes:
The proper way to do it is to have
1 mesh for the graphical road - UV mapped, textured
This can be as low poly as possible (so easy to work with), but high enough not to show harsh angles, especially in curved areas.
1 mesh for the physics surface
Now THIS one has to be high poly - but only if used at full value. Example if you have the straight start/finish line as a flat area, for a couple of hundreds meters and you don't add ANY details (camber, bumps, .. ) then there is no point in doing it high poly - it will feel exactly the same way.
If, on the other way, you would use some artificial method to add some imperfections, that is where it all starts to make sense.
Why 2 separate layers ?
Kunos never made any official statement about it (as far as I know), but 2 aspects come to mind: 1/ if you start playing with the mesh and deform it, it can quickly become difficult to do proper texturing - it will get stretched in all directions
and 2/ physics mesh is hidden. So even if it has lots of verts, they aren't really rendered so I reckon (not 100% sure) the method combined can greatly improve performance.
@liquido - so no LODs required on road imo.
And then comes the fun part:
If you like to add details, you can always add meshes on top - for scratches, skid marks, paint marks, dust, particles, etc. What is the limit ? Balance between the artist's view and performance I'd say.

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