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Followup on Graphics3D rendering problem

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  • Subject: [mg35754] Followup on Graphics3D rendering problem
  • From: AES <siegman at>
  • Date: Mon, 29 Jul 2002 03:13:29 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

I've been warned by others in the past that there is some serious flaw 
in Mathematica's PostScript rendering of 3D graphics, and now I'm 
running into it in a big way.

I'm making a series of, in essence, "3D bar charts" using Graphics3D and 
Show to display vertical towers (Line[]s) of varying heights rising 
vertically from different points in a base plane; and some of the towers 
just aren't there -- just don't draw -- randomly as far as I can tell.  

A given tower will be there in one plot of a sequence, missing in the 
next one (when its height has changed somewhat), reappear a few plots 
later, and so on -- typically only one such tower in a given sequence of 

This is causing me trouble big time.  Is there a workaround?  Specific 
commands or options I should avoid?

Two add'l notes:

1)  As a work-around I replaced all the thick Line[]s in the graphics 
with long skinny Cuboid[]s, and did not observe any of those to be 
randomly missing in any case I've tried to date.

2)  I also realized that certain other Line[]s in my graphic were long 
enough to extend outside the PlotRange I had set in the Show[] command.  
After I corrected this, the randomly missing Line[] problem seemed to go 
away even when using Line[]s.

That was a programming error on my part, but I think nonetheless also 
still a bug in Mathematica's rendering code:

*  PlotRange is essentially a windowing or masking command -- it's 
supposed to let you generate graphic elements that extend outside the 
plot range, then just not display them, right?  (At least it does in 
many other cases.)

*   The Line[]s that randomly disappeared were not the Line[]s that ran 
outside the plotting range, and had no direct connection to them -- and 
they only disappeared in certain plots, while the overlength Line[]s 
were present in all the plots.

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