[vos-d] thought problem 1: physics

[chris]

On 2/2/07, Peter Amstutz <tetron at interreality.org> wrote:
> Well, I assume this is a trick question.  Obviously it *should* do the
> same thing, but because of tiny changes in floating point precision,
> that isn't guaranteed, and the further you go the less likely it is to
> produce the same results.  Do I get a cookie?

yup - even tho it is only 10m the difference can be surprisingly large
and obvious just from looking at image: out of proportion to the
difference in resolution at 10m (which is about 1.6 x 10^-15). See
attached image.

chris
>
> On Fri, Feb 02, 2007 at 09:26:43AM +0900, chris wrote:
> > This is in response to Reed's question in earlier thread.
> >
> > Thought problem 1: physics
> >
> > Suppose I am going to do a rigid body simulation. I put one box (box1)
> > on a plane, at the origin and hold another box (box2) suspended a
> > meter above the plane nearby. I release box2 at time t=20 and it
> > bounces, perhaps collides with box1 then eventually comes to rest. I
> > snap an image of the rest state of the sim.
> >
> > Now I repeat the entire sim after first shifting everything (boxes and
> > plane) by 10m. The boxes and plane are in exactly the same relative
> > position as before. I drop box2 at t=20, let it bounce and snap an
> > image of the sim when it is at rest.
> >
> > Question: will the two images of the two experiments show box2 in the
> > same rest position relative to box1?
> >
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>
> --
> [   Peter Amstutz  ][ tetron at interreality.org ][ peter.amstutz at gdit.com ]
> [Lead Programmer][Interreality Project][Virtual Reality for the Internet]
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