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Special: 
[DAT] (requires LDraw-compatible viewer)
Subject: 
Re: Primitives and quads/triangles
Newsgroups: 
lugnet.cad
Date: 
Wed, 16 Oct 2002 17:58:32 GMT
Viewed: 
536 times
  
In lugnet.cad, Niels Karsdorp writes:
In lugnet.cad, Travis Cobbs writes:
In lugnet.cad, Niels Karsdorp writes:
When I was working on the old Type I trainbase 6 x 12,
I also wanted correct wheels for this part. Since I have
these, I tried to create the wheel. In my first attempt
I used primitives only, but the cones looked horrible
when rendered. In my seccond attempt I created a small
segment (of 5.625 degrees) and created a whole wheel
of 64 segments. This part contains over 700 quads and
over 700 lines. In a third attempt I used primitives
for discs, rings and cylinders, and quad-segments for
the cones (64 segments in a circle).

While your goal is to create something that looks good after L3P has
converted it to POV format, bear in mind that it should ideally also look
good in the original LDraw format.  Using primitives for the cylinders, and
not for the cones will cause problems when rendered with a standard LDraw
renderer.

I would agree with Tore's suggestion to use the 0 IFPOV method.  Use
primitives for both the cylinders and cones to look as good as possible with
standard renderers, and 0 IFPOV to look great in POV.  This would of course
require more work on your part.

I do have one question, though.  I notice that the new-style train wheel
appears to use one cone for each conical section, while you obviously used
multiple.  Is that because they are different sized cones?  Also, are yours
not quite the right size?  There are gaps visible, and if the cones met up
exactly I don't think the gaps would be visible.

The new-style train wheel (4180d.dat) does not use cones, but quads.
This causes gaps when rendered (see on my site).
Since there was not a single matching cone primitive, I used three.
I know about the gaps between these cones. Because of the gaps between
the outer edge of the cone and the surrounding cylinder, I did not spend
more time on alligning the three cones.

I will try to learn more about POV and create two versions of the wheel
in one file, using 0 IFPOV etc., so the part will look good in both
LDraw viewers and POV renders.

(I just received some old 4-stud trainwheels, so these will be added
to my to-do-list, too)

I have created a fourth version, using primitives for cylinders and rings.
Cones I have created with 16 segment quads for LDraw and a true cone for
PovRay (using 0 L3P IFPOV etc.). The results are great!

Now I need to find out how type 5 lines are created......
My wheel so far is:
(The cone at the front needs type 5 lines)

0 Train Wheel Car Type II
0 Name: xxxxx.dat
0 Author: Niels Karsdorp

0 Axle connector
1 16 0 0 -8 4 0 0 0 0 4 0 4 0 4-4disc.dat
1 16 0 0 10 4 0 0 0 0 4 0 -18 0 4-4cyli.dat
1 16 0 0 10 8 0 0 0 0 8 0 -2 0 4-4cyli.dat
1 16 0 0 10 4 0 0 0 0 4 0 4 0 ring1.dat
1 16 0 0 -8 4 0 0 0 0 4 0 4 0 4-4edge.dat
1 16 0 0 10 4 0 0 0 0 4 0 4 0 4-4edge.dat
1 16 0 0 10 8 0 0 0 0 8 0 8 0 4-4edge.dat
0 Wheel 'flens' rear
1 16 0 0 8 4 0 0 0 0 4 0 4 0 ring2.dat
1 16 0 0 8 2 0 0 0 0 2 0 2 0 4-4ring6.dat
1 16 0 0 8 14 0 0 0 0 14 0 14 0 ring1.dat
1 16 0 0 8 8 0 0 0 0 8 0 8 0 4-4edge.dat
1 16 0 0 8 28 0 0 0 0 28 0 28 0 4-4edge.dat
0 Wheel 'flens' edge
1 16 0 0 8 28 0 0 0 0 28 0 -2 0 4-4cyli.dat
1 16 0 0 6 28 0 0 0 0 28 0 28 0 4-4edge.dat
0 Wheel 'flens' cone
0 L3P IFPOV
0 cone{<0,0,6>,28 <0,0,3>,20 open}
0 L3P ELSEPOV
4 16 20 0 3 18.48 -7.65 3 25.87 -10.72 6 28 0 6
5 24 20 0 3 28 0 6 18.48 -7.65 3 18.48 7.65 3
4 16 18.48 -7.65 3 14.14 -14.14 3 19.8 -19.8 6 25.87 -10.72 6
5 24 18.48 -7.65 3 25.87 -10.72 6 14.14 -14.14 3 20 0 3
4 16 14.14 -14.14 3 7.65 -18.48 3 10.72 -25.87 6 19.8 -19.8 6
5 24 14.14 -14.14 3 19.8 -19.8 6 7.65 -18.48 3 18.48 -7.65 3
4 16 7.65 -18.48 3 0 -20 3 0 -28 6 10.72 -25.87 6
5 24 7.65 -18.48 3 10.72 -25.87 6 0 -20 3 14.14 -14.14 3
4 16 0 -20 3 -7.65 -18.48 3 -10.72 -25.87 6 0 -28 6
5 24 0 -20 3 0 -28 6 -7.65 -18.48 3 7.65 -18.48 3
4 16 -7.65 -18.48 3 -14.14 -14.14 3 -19.8 -19.8 6 -10.72 -25.87 6
5 24 -7.65 -18.48 3 -10.72 -25.87 6 -14.14 -14.14 3 0 -20 3
4 16 -14.14 -14.14 3 -18.48 -7.65 3 -25.87 -10.72 6 -19.8 -19.8 6
5 24 -14.14 -14.14 3 -19.8 -19.8 6 -18.48 -7.65 3 -7.65 -18.48 3
4 16 -18.48 -7.65 3 -20 0 3 -28 0 6 -25.87 -10.72 6
5 24 -18.48 -7.65 3 -25.87 -10.72 6 -20 0 3 -14.14 -14.14 3
4 16 -20 0 3 -18.48 7.65 3 -25.87 10.72 6 -28 0 6
5 24 -20 0 3 -28 0 6 -18.48 7.65 3 -18.48 -7.65 3
4 16 -18.48 7.65 3 -14.14 14.14 3 -19.8 19.8 6 -25.87 10.72 6
5 24 -18.48 7.65 3 -25.87 10.72 6 -14.14 14.14 3 -20 0 3
4 16 -14.14 14.14 3 -7.65 18.48 3 -10.72 25.87 6 -19.8 19.8 6
5 24 -14.14 14.14 3 -19.8 19.8 6 -7.65 18.48 3 -18.48 7.65 3
4 16 -7.65 18.48 3 0 20 3 0 28 6 -10.72 25.87 6
5 24 -7.65 18.48 3 -10.72 25.87 6 0 20 3 -14.14 14.14 3
4 16 0 20 3 7.65 18.48 3 10.72 25.87 6 0 28 6
5 24 0 20 3 0 28 6 7.65 18.48 3 -7.65 18.48 3
4 16 7.65 18.48 3 14.14 14.14 3 19.8 19.8 6 10.72 25.87 6
5 24 7.65 18.48 3 10.72 25.87 6 14.14 14.14 3 0 20 3
4 16 14.14 14.14 3 18.48 7.65 3 25.87 10.72 6 19.8 19.8 6
5 24 14.14 14.14 3 19.8 19.8 6 18.48 7.65 3 7.65 18.48 3
4 16 18.48 7.65 3 20 0 3 28 0 6 25.87 10.72 6
5 24 18.48 7.65 3 25.87 10.72 6 20 0 3 14.14 14.14 3
0 L3P ENDPOV
0 Wheel edge 'loopvlak'
1 16 0 0 3 20 0 0 0 0 20 0 -13 0 4-4cyli.dat
1 16 0 0 3 20 0 0 0 0 20 0 20 0 4-4edge.dat
1 16 0 0 -10 20 0 0 0 0 20 0 20 0 4-4edge.dat
0 Wheel front
1 16 0 0 -10 1 0 0 0 0 -1 0 -1 0 1-4rin19.dat
1 16 0 0 -10 0 0 -1 -1 0 0 0 -1 0 1-4rin19.dat
1 16 0 0 -10 -1 0 0 0 0 1 0 -1 0 1-4rin19.dat
1 16 0 0 -10 0 0 1 1 0 0 0 -1 0 1-4rin19.dat
1 16 0 0 -10 19 0 0 0 0 19 0 19 0 4-4edge.dat
0 L3P IFPOV
0 cone{<0,0,-6>,16 <0,0,-10>,19 open}
0 L3P ELSEPOV
4 16 16.0000 0.0000 -6 14.7821 6.1229 -6 17.5537 7.2710 -10 19.0000 0.0000 -10
4 16 14.7821 6.1229 -6 11.3137 11.3137 -6 13.4350 13.4350 -10 17.5537 7.2710 -10
4 16 11.3137 11.3137 -6 6.1229 14.7821 -6 7.2710 17.5537 -10 13.4350 13.4350 -10
4 16 6.1229 14.7821 -6 0.0000 16.0000 -6 0.0000 19.0000 -10 7.2710 17.5537 -10
4 16 0.0000 16.0000 -6 -6.1229 14.7821 -6 -7.2710 17.5537 -10 0.0000 19.0000 -10
4 16 -6.1229 14.7821 -6 -11.3137 11.3137 -6 -13.4350 13.4350 -10 -7.2710
17.5537 -10
4 16 -11.3137 11.3137 -6 -14.7821 6.1229 -6 -17.5537 7.2710 -10 -13.4350
13.4350 -10
4 16 -14.7821 6.1229 -6 -16.0000 0.0000 -6 -19.0000 0.0000 -10 -17.5537
7.2710 -10
4 16 -16.0000 0.0000 -6 -14.7821 -6.1229 -6 -17.5537 -7.2710 -10 -19.0000
0.0000 -10
4 16 -14.7821 -6.1229 -6 -11.3137 -11.3137 -6 -13.4350 -13.4350 -10 -17.5537
-7.2710 -10
4 16 -11.3137 -11.3137 -6 -6.1229 -14.7821 -6 -7.2710 -17.5537 -10 -13.4350
-13.4350 -10
4 16 -6.1229 -14.7821 -6 0.0000 -16.0000 -6 0.0000 -19.0000 -10 -7.2710
-17.5537 -10
4 16 0.0000 -16.0000 -6 6.1229 -14.7821 -6 7.2710 -17.5537 -10 0.0000
-19.0000 -10
4 16 6.1229 -14.7821 -6 11.3137 -11.3137 -6 13.4350 -13.4350 -10 7.2710
-17.5537 -10
4 16 11.3137 -11.3137 -6 14.7821 -6.1229 -6 17.5537 -7.2710 -10 13.4350
-13.4350 -10
4 16 14.7821 -6.1229 -6 16.0000 0.0000 -6 19.0000 0.0000 -10 17.5537 -7.2710 -10
0 L3P ENDPOV
0 Wheel inside
1 16 0 0 5 16 0 0 0 0 16 0 -11 0 4-4cyli.dat
1 16 0 0 5 8 0 0 0 0 8 0 8 0 ring1.dat
1 16 0 0 5 8 0 0 0 0 8 0 -15 0 4-4cyli.dat
1 16 0 0 -10 8 0 0 0 0 8 0 8 0 4-4disc.dat
1 16 0 0 -6 16 0 0 0 0 16 0 16 0 4-4edge.dat
1 16 0 0 5 16 0 0 0 0 16 0 16 0 4-4edge.dat
1 16 0 0 5 8 0 0 0 0 8 0 8 0 4-4edge.dat
1 16 0 0 -10 8 0 0 0 0 8 0 8 0 4-4edge.dat
1 16 0 0 -10 1 0 0 0 0 -1 0 1 0 stud.dat
0 Spokes
1 16 0.000 12.000 5 0 0 1 4 0 0 0 -11 0 box3#8p.dat
1 16 7.053 9.708 5 -2.35114 0 -0.809017 -3.23607 0 0.587785 0 -11 0 box3#8p.dat
1 16 11.413 3.708 5 -3.80423 0 -0.309017 -1.23607 0 0.951057 0 -11 0 box3#8p.dat
1 16 11.413 -3.708 5 -3.80423 0 0.309017 1.23607 0 0.951057 0 -11 0 box3#8p.dat
1 16 7.053 -9.708 5 -2.35114 0 0.809017 3.23607 0 0.587785 0 -11 0 box3#8p.dat
1 16 0.000 -12.000 5 0 0 1 4 0 0 0 -11 0 box3#8p.dat
1 16 -7.053 -9.708 5 -2.35114 0 -0.809017 -3.23607 0 0.587785 0 -11 0
box3#8p.dat
1 16 -11.413 -3.708 5 -3.80423 0 -0.309017 -1.23607 0 0.951057 0 -11 0
box3#8p.dat
1 16 -11.413 3.708 5 -3.80423 0 0.309017 1.23607 0 0.951057 0 -11 0 box3#8p.dat
1 16 -7.053 9.708 5 -2.35114 0 0.809017 3.23607 0 0.587785 0 -11 0 box3#8p.dat
0



Niels



Message has 1 Reply:
  Re: Primitives and quads/triangles
 
(...) Looks good in my program (LDView), once I got the file modified back to its original form due to the posting causing some lines to wrap. Looking at the file, I think it would require new cone primitives to allow the use of cone primitives (...) (22 years ago, 16-Oct-02, to lugnet.cad)

Message is in Reply To:
  Re: Primitives and quads/triangles
 
(...) The new-style train wheel (4180d.dat) does not use cones, but quads. This causes gaps when rendered (see on my site). Since there was not a single matching cone primitive, I used three. I know about the gaps between these cones. Because of the (...) (22 years ago, 16-Oct-02, to lugnet.cad)

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