Re: [Algorithms] Rendering (a portion of) a Plane

[Anceschi M. <anc...@li...>]

----- Original Message -----
From: "Steve Wood" <Ste...@im...>
To: <gda...@li...>
Sent: Friday, July 21, 2000 9:25 PM
Subject: RE: [Algorithms] Rendering (a portion of) a Plane


> Hmm,
>
> Your equation:
> Normal[0] * X + Normal[1] * y + Normal[2] * z + distance = 0
>
> is defining 3D space as an infinite number of parallel planes with the
same
> Normal as in the equation:
> Normal[0] * X + Normal[1] * y + Normal[2] * z = 0
>
> using an index of distance to determine which parallel plane you are
> referencing.
> Normal[0] * X + Normal[1] * y + Normal[2] * z = -distance
>
> Correct me if I'm wrong, but it sounds like you want to find points ON the
> plane...if you are trying to describe a circle on the plane then you want
> all points (x,y,z) which lie on the plane and which are the same distance
> from your point of origin (x',y',z').  If you like matrices and
> transformations then perhaps use the 2D (x,y) coordinate plane to find
your
> points x^2 + y^2 = distance, then translate and rotate them onto your
plane.
>
> R&R
>
>
> > -----Original Message-----
> > From: Jeremy Bake [mailto:Jer...@in...]
> > Sent: Friday, July 21, 2000 6:57 AM
> > To: 'gda...@li...'
> > Subject: [Algorithms] Rendering (a portion of) a Plane
> >
> >
> > I've been working on my viewport culling and I just wanted to
> > test something
> > out
> > I was wondering if anyone could tell me how to render a
> > portion of a plane
> > around
> > a particular point using the
> > Normal + distance version of a plane.
> > I think it relates to
> > Normal[0] * X + Normal[1] * y + Normal[2] * z + distance = 0
> > but I can't seem to get my head around how I could draw this function
> > over a specific range...  any help would be Greatly appreciated
> >
> > Jeremy Bake
> > RtroActiv
> >
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> >
>
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thanks!!!!!!!

mauro