Vehicle-Terrain collision with 20000 vehicles

[tom83]

Hello,

I am developing a vehicle simulation that has up to 20000 vehicles. Until now we had terrain with a grid resolution of 12.5 meter and because we get a new terrain engine with a grid resolution of .5 meters the old suspension simulation does not work anymore because the terrain is much steeper.

The reason is that we do not have a physics based vehicle-terrain collision. What happens now is that vehicles drive into the terrain and then fly upwards which looks quite funny, which is shown in the appended image.

The way i want to solve this is by adding support for bullet. The problem is that bullet can never support 20000 vehicles at the same time. To solve this I just want to simulate a blob of vehicles (less than 100) around the user with bullet. This means that vehicles keep flying outside the blob, which is bad. Also using bullet for the terrain vehicle collision seems overkill.

The question here is if I am on the right path here or should I do it in another way with a custom solution. I really only want to have a correct terrain-vehicle collision to keep vehicles from flying (they should instead collide with a steep slope and stop) nothing else.

Tom

[benelot]

What you want to achieve sounds pretty crazy. I am asking myself why you would want to simulate up to 20k vehicles. However, I think that you will have to fix your approximative part of your simulation. Apparently Bullet can not help here a lot, because it can not simulate all the cars. You could replace the cars with a single raytracing agent so that it can find out the slope it is currently facing when moving into the current direction. However, our problem will be how to minimize the simulation error between your approximation and your actual vehicles simulated with bullet. It is definitely true that you need to reduce the number of simulated cars.