Slow gravity

[Gogo]

Hi,

I'm quite new to Bullet and physics engines in general, but I have been trying to implement Bullet in my current iphone project. I've successfully added it to my project and have set up a test scene (512x512 ground plane and a sphere with radius = 16, i.e somewhat based on the Hello World tutorial) which seems to work okay. However, it strikes me that the gravity force (set as (0,-10,0) appears to be very weak, resulting in the sphere taking longer to fall than I'd expect it to.

Increasing the gravity value to compensate by a factor of 100 seems to get 'better' (i.e more realistic) results but I sense this isn't really the correct way to go. Is there something I'm missing to all of this..? I've read the wiki section entitled "Scaling the world" but that doesn't seem to be directly related to what I'm seeing wrt to gravity.

Any pointers on this would be greatly appreciated. Thanks!

[Erwin Coumans]

As units are assumed to be in meters, with gravity in 9.8 m/s^2, a 16 meter sphere is huge and appears to move in slow-motion. Please try to use 1.6 or .3 for the radius and see if that helps.

The Wiki documentation has been updated: http://www.bulletphysics.com/mediawiki- ... _The_World

Thanks for the feedback,
Erwin

[Gogo]

Ah, I guess that does makes sense when I think about it some more. Like I say, I am quite new to physics engines really Will try scaling my world accordingly then and see how it goes.

Btw on an unrelated note, I would like to express my thanks for releasing the Bullet library under such a liberal license. It really does seem to be quite a godsend for all the non-mathematically inclined people out there, such as myself! Many thanks!