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title = "Geodome: Geodome creation for POV-Ray"
keywords = "geodome,geodesic dome,ray tracing,POV-Ray"
description = "Geodome: Geodome creation utility for POV-Ray"
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Copyright © 1994-97 Andy Wardley. All Rights Reserved.
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Geodome is a utility to create data files for the POV-Ray
ray tracer, Version 2.x and onwards. It creates geodesic spheres that
consist of triangular facets (FACET mode) or a mesh of pipes and joints
(MESH mode).
For further information on POV-Ray, check out the official POV-Ray
web site:
Further examples of Geodome output can be found on the
Digital Artist pages.
Download:
Contents
Copyright, License and Distribution Terms
Geodome is freely distributed software. No charge or registration
fee is required for using the program and it may be distributed by any
electronic or magnetic media providing the package is complete and
unchanged.
No charge may be made for the program expect a small handling charge or
for media supplied. The program may not be sold in any other way without
the express permission of the author, Andy Wardley
<abw@peritas.com>
No guarantees or warranties are made with the program and the author can
accept no responsibility for any damages or losses incurred through using
this program. I hate having to say that.
Usage
Run Geodome with the -h option to display the help/command
summary screen:
GEODOME V1.2 21-Jan-97 Geodome generator for POV-Ray V2.n+
Copyright (C) 1994-97 Andy Wardley . All Rights Reserved
usage:
geodome [options]
-h This help
-v verbose mode
-r depth recursion depth (default: 3)
-f generate triangular facets (default)
-m generate pipe mesh
-p radius pipe radius (mesh only) (default: 0.0100)
-j radius joint radius (mesh only) (default: 0.0150)
If no options are specified, a faceted geodome is created with a recursion
level (see below) of 3. The data is sent to the standard output (stdout)
and should be redirected to a file using the '>' operator.
e.g.
geodome > geodome.inc
In the above example, the output is sent to a file named "geodome.inc"
which will contain something like the following (edited for brevity):
/*
* Geodome model data created by geodome V1.2 21-Jan-97
*
* geodome is free software by Andy Wardley
* http://www.peritas.com/~abw
*/
#declare geodome_eighth =
union {
triangle {
<0.0000000000, 1.0000000000, 0.0000000000>
<0.0000000000, 0.9807852804, 0.1950903220>
<0.1950903220, 0.9807852804, 0.0000000000>
}
[...snip...]
triangle {
<0.6396021491, 0.4264014327, 0.6396021491>
<0.6396021491, 0.6396021491, 0.4264014327>
<0.4264014327, 0.6396021491, 0.6396021491>
}
}
#declare geodome_hemisphere =
union {
object { geodome_eighth }
object { geodome_eighth rotate <0, 90, 0> }
object { geodome_eighth rotate <0, 180, 0> }
object { geodome_eighth rotate <0, 270, 0> }
}
#declare geodome =
union {
object { geodome_hemisphere }
object { geodome_hemisphere rotate <180, 0, 0> }
}
You can then #include this file into a povray scene file and use the
defined objects "geodome_eighth", "geodome_hemisphere" and "geodome" as
you require. The effective radius of the geodome is 1 unit and it is
centred on the origin. The object can be scaled and translated as required.
The verbose option (-v) causes Geodome to print a summary of
the active parameters to the standard error output (stderr).
Options
-h Help.
-v Verbose mode. Parameter summary is printed on stderr.
-r depth This option sets the recursion depth. If none is
specified, it defaults to 3.
Geodome works by taking a triangle and sub-dividing it into a further 4
triangles. Each of these is then sub-divided, and so on. The recursion
depth specifies how many times this happens.
A depth of 1 means that each "side" (i.e. eighth) of the dome has 4 triangles.
Depth 2 gives 16 (4 * 4), 3 gives 64 (4 * 4 * 4), 4 gives 256, and so on.
As you can see, it's not long before the number gets very large. At high
recursion depths, it's likely you'll end up waiting a long time, assuming
that you don't run out of memory or disk space first.
-f FACET mode - specifies that the geodome should be
constructed from a series of triangular facets.
This is the default and can safely be ignored.
-m MESH mode - specifies that the geodome should be
constructed from a series of pipes (cylinders) and
joints (spheres).
When the -m option is used to specify MESH mode, the -p and -j options can
be applied. If the -f option is used, the -p and -j options are ignored.
-p radius Specifies the radius of the pipes that consist
the framework. This defaults to 0.01 units.
-j radius Specifies the radius of the joints connecting
the pipes. This defaults to 0.015 units.
Examples of Use
geodome Default operation (facets, recursion depth 3).
geodome -r 2 Create facets with recursion depth 2.
geodome -m Create a mesh (use default pipe and joint widths).
geodome -m -j 0.02 Mesh with joint radius of 0.02.
Compiling Geodome
The source code is distributed with Geodome to allow you to compile it
for your own system. The code compiles cleanly on a SVR4 UNIX machine,
but is untested on any other system. Maths library is required and
getopt(3C) must be available (there is a getopt available as part of the
GNU C library if your compiler doesn't support it directly). Pre-compiled
Geodome versions are available for the PC (MS-DOS) and a handful
of other selected platforms.
On most UNIX systems, something like the following should suffice:
cc -o geodome geodome.c -lm
Geodome may be distributed freely as long as it is in its original
form complete with all files, copyright messages, documentation, etc.
Modified versions of the program may not be distributed without express
permission of the author.
You are encouraged to modify, update or improve Geodome and submit your
modified version to the author for perusal or inclusion in further versions
of Geodome. Be aware though, that a major re-write is currently
underway (read: "has been for 2 years now") so don't re-invent the same
wheel without checking first.
Geodome version 2.0 will will be finished Real Soon Now.
History
Changes from version 1.1 to 1.2:
- FACET mode now specified by -f option, replacing previous -t (triangle)
option. This is to bring Geodome (1.x versions) into line with
the forthcoming Geodome 2.0.
- Help option and verbose option added (again, for future compatibility).
- Major code overhaul and tidy-up.
- Documentation changes to reflect code updates, new email address, etc.
Bugs
- The resultant geodome is symetrical around each axis (x, y, z). This
is not ideal or indeed correct for a true geodesic dome. It is,
however, a by-product of the simplistic generation algorithm used.
This will be handled correctly in future versions.
Author Information
Geodome was written by Andy Wardley.
Please contact me (preferably by email) if you have any comments,
criticisms, suggestions or even praise!
- Email:
- abw@peritas.com
- On the Web:
-
http://www.peritas.com/~abw
(Home Page)
- Real Life Address: (to send money, gifts, postcards, etc.)
- Andy Wardley
c/o Peritas Multimedia
Beaumont
Burfield Road
Old Windsor
Berkshire.
SL4 2JP
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