Re: 3D plot symbols

[rkj(at)dukebar.crml.uab.edu (R. Kyle Justice)]

David Fanning (davidf@dfanning.com) wrote:
: R. Kyle Justice (rkj@dukebar.crml.uab.edu) writes:
:  
: > I would like to be able to create a 3-D scatter plot
: > with 3-D symbols.  It would be nice if I could define
: > a cube with USERSYM.  I can almost get what I want
: > using PLOTS but the symbols are "flat" in 3-D.

: I have a feeling the PLOTS symbols are "flat" 
: because you forgot to set a T3D keyword on the 
: PLOTS command. :-)

I am using the T3D keyword.  The reason the symbols are
flat is because they have no depth.  USERSYM only takes
x and y vertices.  The plot is rendered properly, even 
the symbols.  They appear flat because they only have
1 side (actually 2, I guess; front and back).


: I can't see any reason why 3D symbols with PLOTS
: would be prohibited, even in PV-Wave, which I
: assume you are using.

Yep, I am primarily using PV-Wave but I don't really see
a way to get 3-D symbols in IDL either, at least not 
with USERSYM.  Is there a way to make 3-D symbols?  This
would be a nice feature, especially since the 2-D symbols
appear to be rendered as if they are 3-D.


: > Can I get this functionality using the polygon 
: > rendering routines?  I am particularly worried about
: > speed since the plot will be animated (continuously
: > updated as symbol values change).

: I think speed will be a problem using PLOTS. I'd 
: offer you something in the line of object graphics
: 3D scatterplots, but I doubt it would apply. :-(

It appears to be fast enough for my purposes with 2-D
symbols.  If I have to use the polygon routines I'm
sure to get a big slowdown, even if I knew what I 
was going (and I don't).

Why does the object graphics suggestion not surprise
me ;-)


: Cheers,

: David

Kyle