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Subject: 
Re: Conditional lines on sloped wedge parts 43720 and 43721
Newsgroups: 
lugnet.cad.dat.parts
Date: 
Wed, 27 Apr 2005 00:08:52 GMT
Viewed: 
4751 times
  
In lugnet.cad.dat.parts, Niels Karsdorp wrote:
In lugnet.cad.dat.parts, Lars C. Hassing wrote:

In lugnet.cad.dat.parts, Steve Bliss wrote:

I'm pretty sure that's going to be the problem with *any* partition of this
surface into polygons.  Having a mathematical description of the surface would
be good, because then we could potentially create a primitive for the surface,
and rendering programs could substitute a smooth-curve construct for the
primitive.

I have made a 43720.inc for the test of the coming L3PPARTS.
The mathematical description of the surface is:
   80x + 40y + yz = 0
and I have used the POV primitive quadric:
   quadric {
      <0,0,0>, <0,0,1>, <80,40,0>, 0
      clipped_by { box { <-20,0,-40>, <0,20,40> } }
   }


Looks good.
Should we create a new primitive with the next dimensions:?
2 24 0 0 1 0 1 1
2 24 1 0 -1 0 1 -1
2 24 0 0 1 1 0 -1
2 24 0 1 1 0 1 -1
and a POV-quadric version in the coming L3PPARTS.

As the outer twisted surface of the parts with this shape are
pretty the same size, the inner surface differs among these parts
(in 43720/43721 the inner surface has a z-size of 72,
in 45407 the inner suface has a z-size of 76).
With a general primitive it can be stretched to any dimension.

Good idea with a twist primitive (twist.dat ?).
Perhaps it would be simpler if it were only in one octant:
    2 24 0 0 0  0 0 1
    2 24 0 0 1  1 1 1
    2 24 1 1 1  0 1 0
    2 24 0 1 0  0 0 0
POV code would be:
    //x - yz = 0
    quadric {
       <0,0,0>, <0,0,-1>, <1,0,0>, 0
       clipped_by { box { <0,0,0>, <1,1,1> } }
    }
/Lars



Message has 1 Reply:
  Re: Conditional lines on sloped wedge parts 43720 and 43721  [DAT]
 
(...) Ok so it's been a few years, but I took another look at this. Did anybody ever make a twist primitive? It appears like all you need to do is something like this. Don 0 Wedge 4 x 2 Sloped Left 0 Name: 43721.dat 0 Author: Donald Sutter 0 (...) (14 years ago, 22-Sep-10, to lugnet.cad.dat.parts)

Message is in Reply To:
  Re: Conditional lines on sloped wedge parts 43720 and 43721  [DAT]
 
(...) Looks good. Should we create a new primitive with the next dimensions:? 2 24 0 0 1 0 1 1 2 24 1 0 -1 0 1 -1 2 24 0 0 1 1 0 -1 2 24 0 1 1 0 1 -1 and a POV-quadric version in the coming L3PPARTS. As the outer twisted surface of the parts with (...) (20 years ago, 25-Apr-05, to lugnet.cad.dat.parts)

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