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

[Steve W. <Ste...@im...>]

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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