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Author: phi | Created: 2017-10-06 18:48:10
Subject: TORCS and Cars going into the Ground
Hi all

I made some highly textured and highly modeled cars. They worked well in TORCS 1.3.7, but when it came to 1.3.8 they sank well into the ground at high speeds or in braking, and I had to increase the pressure of the front suspension to correct the effect.

Is this expected, given the assumption that the whole car must have a well-balanced configuration, or does the TORCS have any shortcomings in relation to the collision code?

Last Edited: 2017-10-06 18:48:10 by phi
    Author: berniw | Created: 2017-10-07 04:42:41
    Subject: Re: TORCS and Cars going into the Ground

    What do you mean by "sank into the ground", did you compare the exact same scenario on 1.3.7 vs. 1.3.8? Does just the 3D Model clip the ground or does anything else happen? Where does it happen? If it is just clipping, check:
    - Is it on a track like ole-road? Some minimal clipping there is normal, because the visual 3D-Model of the track does not match the physical model (a quad polygon is for rendering approximated as 2 triangles, but the computational model treats it currently as one, eventually non flat surface)
    - Ground floor of the car 3D-model, needs to be at 0, not lower
    - The car 3D-model center must be in the center of the coordinate system, see also my tutorial video on youtube, you can check it by bumping into track barriers, check for gaps or clipping.

    In fact the collision/wheel-z code in 1.3.8 works better than ever, because it works now with the car edges. But that this works, the car centering must be correct (till 1.3.7 it happened at the car axles, so the centering was not relevant for that).

    You can see the difference very well on dirt-2, do a comparison run with 1.3.7 and 1.3.8 where the cars jump and hit the floor on an angle (use e.g. olethros or bt bots, they do not slow down over the jumps). In 1.3.7 the parts before/behind the axle dive deep into the ground, in 1.3.8 this does not happen anymore.

    Kind regards


    Last Edited: 2017-10-07 11:44:10 by berniw
      Author: phi | Created: 2017-10-07 13:19:04
      Subject: Re: TORCS and Cars going into the Ground
      The 3D model worried me a lot at the time, and I spent a lot of time on tests about its center, without any results. I do not remember doing what I remembered today: test with a configurable and graphically stable car: car7-trb1 in Forza; I believe you can replicate the phenomenon: put the front spring suspension at 500 lbs/in, and the car dips underground at high speed -- my cars do that at 2000 lbs/in (4000 solves the problem).

      EDIT: I do not have 1.3.7 to check if car7-trb1 behaves this way in it, but my cars worked well at 2000 lbs/in.
      Last Edited: 2017-10-07 14:36:18 by phi