In my struggle to stabilize my 3DGS car I've stumbled upon a very annoying fact: real-world cars have very low centers of mass, thanks to intelligent component design and placement, but 3DGS objects tend to have their center of mass in the geometric center of their mass polygons. To realistically model a car I'd need to reposition my center of mass a little more towards the lower part of the car (and in the specific case of a racing midship-rear-engine car a little more to the rear as well). Has anyone else stumbled upon this problem ? Is there a workaround ?

Perhaps you could constrain an invisible, passable physics entity of the
appropriate size to the bottom of the car?

I sure hope that's not the only solution, but it can be implemented if there's no native way to manipulate the center of mass.

So here goes my suggestion to the physics engine: a 3-dimensional vector for manipulating the center of mass of a physics object

You could make the car out of two connected physic entities. One heavy for the ground and one light for the top (but I don´t know much about the physics engine).

You can also move your model a litle forward in med.

Try to increase the mass of the wheels.

@fogman

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Try to increase the mass of the wheels.

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This is exactly what I've been doing, but it has a very undesireable side effect: with the car weighting only 1 unit and concentrating the weight at the wheels they tend to have a strong gyroscopic effect on the car i.e. during extended air times the wheel rotation heavily influences the pitch/roll of the car (wich, of course, should be kept almost unchanged in free-fall)

@EX Citer:

I'll try to reassemble the car body as two separate models with wheel junctions and lower structure in one and "decorative" upper-body in another and attach them with a phcon_ constraint so I can add proper weight to the lower part. Hopefully it'll get the desired effect.

Thank you all for your input

@EdMercer: The center of mass is always centered. You can change the inertia matrix by choosing a different object type in ph_setmass, but that is only relevant in low-g situations. As fogman suggested, the easiest way to lower the center of gravity is changing the weight ratio of body and wheels. With wheels weighing 4 times as much as the body you can get good results. The other option is a passable&invisible weight entity added to the car via a (fixed) slider.