Some Yahoo wrote:
> On 7/13/2011 1:55 AM, Le_Forgeron wrote:
>> Le 13/07/2011 04:57, Some Yahoo nous fit lire :
>>> I'm looking for a way to calculate the bounce off the interior of a
>>> sphere...
>>>
>>>
>>> I have a position, a velocity vector and my sphere is hollow and
>>> centered at the origin.
>>>
>>> I'm pretty sure that Velocity=-Velocity is not right, though in my 
head
>>> it seems logical.
>>
>> Velocity := -Velocity is correct only when position&  Velocity are
>> aligned (you came through the center of the sphere, you go back to it)

>>
>> For other positions, you need to find the intersection point on the
>> sphere and mirror the velocity in regard to the normal of the sphere a
t
>> that point.
> 
> ok, lets pretend I failed 3D calculus...
> 
> Sphere is <0,0,0>,100
> 
> I can use VDist to see when the marbles hit  each marble has
> 
> position (vector)
> velocity (vector)
> 
	velocity - 2 * dot(velocity, normal) * normal

	Where:
- dot(a, b) := a.x*b.x + a.y*b.y + a.z*b.z is the dot product;
- normal := position / 100 is the unit normal at intersection.

		Jerome
-- 
mailto:jeb### [at] freefr
http://jeberger.free.fr
Jabber: jeb### [at] jabberfr

Post a reply to this message

Attachments:
Download 'us-ascii' (1 KB)