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### Dark Physics & Dark A.I. & Dark Dynamix / Rigid Body Explanation desperately needed...

Message
Posted: 4th Jan 2007 04:41
Ok, got DP and tried my first project. Supposed to be ballistics trainer for a bunch of teenagers, but needs a lot of work yet.

In very little time I was able to get a ball flying around my terrain, bouncing and everything, very cute.

To fire my sphere I'm using something like the following (this is taken from a test program that has values hardcoded).

Note that mode=3 is supposed to add velocity (in units/time)(mass independent). My world is modelled at a scale of 1 unit = 1 meter, so I would expect the ball to go flying off to the right at 4m/s. Not so, the ball goes skizzing off at 106m/s (the test program was written to figger out just how fast it was skizzing).

So I kept winding up with a velocity multiplier of about 26. 26? WTFO. So I kept banging around with this, figuring the 26 was somehow related with the frame rate or the number of substeps or some damn thing that would suddenly make sense.

Well I got the bright idea to set the ball's mass, just to see if it was really mass independent. So I changed the launch code to:

And Wham! ball flies off at 4m/s (well, 4.103 - but who's complaining...).

Very cool. Change mass to 2.0 and ball flies off at 2m/s. Huh?

Help file says
Quote: "
3, velocity change, has unit of distance / time, effect is mass independent
"

To me that means I shouldn't have to set the mass, and even if I do changing it should make no difference. I really think this is wrong. Anyone else?
Posted: 4th Jan 2007 12:57
Sounds wrong to me. I would expect the velocity you apply to a stationary object to be the maximum it can reach, and to immediately start decelerating.