rec.autos.simulators

In most Sim I've seen you translate the cars velocity vectors in the
Worldspace velocity vectors (or some such thing). Then these World
velocity vectors get added to positional co-ordinates.

    car_world_pos += car_world_velocity * delta_t;

Now is it ok to scale your Sim by doing this....

    scale_factor = 10; //(depends on size of model)
    car_world_pos += car_world_velocity * delta_t * scale_factor;

It's only the "Position" I scale nothing else, it seems to work ok,
but it appears that the scale_factor value has to match the car model
size. In my case, scale_factor = 20 to match my model size. (I'm using
A4 Game_Studio & there are min/max limits on sizes of things.)

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com

My little car sim screenshots:
http://performancesimulations.com/scnshot4.htm

Thanks Todd, I hoped as much but was unsure if the rotations needed any adjusting...

Al

It's probably better to try and scale your model (if A4 Game_Studio is
a modeling package). If you program a sim, keeping units to something
you can relate to is quite important, although mathematically it
shouldn't make a difference.

That's why US people stick to pounds, and here in Europe we stick to
kilograms.
And that's why with the new Euro everybody here spends too much money
(it's worth more than twice as much as the old guilder, but doesn't
feel like that). ;-)

Ruud van Gaal
Free car sim: http://www.racer.nl/
Pencil art  : http://www.marketgraph.nl/gallery/

I agree. It definitely makes a difference in world construction,
especially if you ever plan to have more than 1 artist on the project.
The cost in iteration, communication, and wasted work is enormous if
you don't use a standard scale.

How small??

Well, I try to figure out what the smallest object in my world will
be, create it the smallest I can , then scale everything from here. As
I'm the only one doing the project, it's just me who has to worry
about the size of things. I agree it would be nice to have things
real-type-scale but maybe next time...

Aussies of my era are fully conversant with both metric & imperial
measurements but who wouldn't love metric ;) .

Ruud van Gaal
Free car sim: http://www.racer.nl/
Pencil art  : http://www.marketgraph.nl/gallery/

...

As an interesting side-note; Quake3 still uses funny units. (in the
MD3 format for example). A remainder from Doom, or even Castle
Wolfenstein (the old one), where fixed point ruled.
Too bad it's still in there, because it is really is something you
want to abstract yourself from. Enough trouble apart from units.

Ruud van Gaal
Free car sim: http://www.racer.nl/
Pencil art  : http://www.marketgraph.nl/gallery/