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Collisions - Rectangle and Circle

Topics: Developer Forum, User Forum
Jul 22, 2009 at 8:27 PM


I've just starting using your farseer physics engine, which is quite impressive btw,

but have found strange collisions between Circles and rectangles.

If i were to hit a rectangle wall that was position at a 45 degree angle i would expect the circle to bounce off at 45 degree angle if the circle was travelling at a 90 degree angle to the wall.

I'm getting different responces and am wondering if its somthing i'm doing wrong or a known issue with the engine.






Jul 22, 2009 at 9:07 PM

That is perfectly normal. In Farseer Physics Engine we approximate circles with polygons. This is to make the collisions more simply internally in the engine, but comes at the cost of collisions not being 100% real.

You can try tweaking the number of edges on the circle to see if that helps or even turn off rotation on the circle for a more consistent collision response. We have another ongoing thread about this right here.

Jul 22, 2009 at 9:19 PM

Hi, Thanks for the responce.


I've increased the amount of edges, seems to work how i want it.

Thanks for your help