There is, apart from plain ASCII-text, no special CAD file type that Singular directly supports.
(For more advanced communication with external programs see the data type
link http://www.singular.uni-kl.de/Manual/la ... htm#SEC141 .)
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When I want to create some graphics, related to mathematical objects,
I mainly use xfig to produce on the fly a (vector-) graphic.
The process takes three steps, where you may replace the converter by
your favourite one.
1.) With the
write (or the
fprintf) command write plain ASCII text
which encodes the graphic data, like polygon lines, circles, colours,
shading etc.
2.) With the
system command call from inside Singular
the converter fig2dev to get a pdf file.
3.) Again with the
system command, call some viewer, e.g. gv
You will also find these mechanics in the library
resgraph.libhttp://www.singular.uni-kl.de/Manual/la ... tm#SEC1142 which uses the dot program to produce a graphic and xv to display it.
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Another program which may attract your interest is the ray tracer
surf (java-frontend
surfer) to visualize algebraic curves and surfaces.
http://www.imaginary2008.de/surfer.php?lang=en http://sourceforge.net/projects/surf/ (Note that the raytracer does not generate graphics from mesh / convex hull,
but from the equations that describe the coordinates.)
surf can be called directly (similar as described above) from Singular
via the library
surf.lib http://www.singular.uni-kl.de/Manual/la ... tm#SEC1467.