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Re: drawing a single point in 3-D [message #33986]

Tue, 11 February 2003 11:03

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

lyubo (lzagorch@cs.wright.edu) writes:

> I'll go with the polyline. Thanks Rick.

Now wait a minute! I was going to suggest PolyLine,
but you had already ruled it out as impossible to
implement! :-)

Cheers,

David
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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Re: drawing a single point in 3-D [message #33987 is a reply to message #33986]

Tue, 11 February 2003 11:53

lyubo
Messages: 34
Registered: March 2002

Member

I'll go with the polyline. Thanks Rick.

Lyubo

"Rick Towler" <rtowler@u.washington.edu> wrote in message
news:b2bfmj$184m$1@nntp6.u.washington.edu...
>
> "lyubo" wrote in message ...
>
>> How do I draw a single point in 3D?
>
> AFAIK you can't just plot a single point but you have a few options.
>
> The simplest would be to use IDLgrPolyline along with IDLgrSymbol. Set
your
> linestyle to 6 (no line) and set the SYMBOL keyword to an instance of
> IDLgrSymbol. The built in symbols are 2d, but you can roll your own 3d
> symbols. I would assume you can use VERT_COLORS to color the points
> accordingly.
>
>
>> I have to display a large number of points in 3-D and using a polyline
>> (or texture mapped polygons) isn't an option. Is there any other way?
>
> Since you need to display a "large" number of points I think polyline is
the
> only way to go. If you create your own symbol, keep the number of verts
as
> low as possible. A cube symbol will probably look like a dot at the scale
> you will be drawing it at.
>
> The only other option would be using IDLgrPolygon to represent a point.
For
> a large number of points this is a less than optimum approach as too many
> atoms in the graphics tree slow the drawing process considerably.
>
> -Rick
>
>

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Re: drawing a single point in 3-D [message #33988 is a reply to message #33986]

Tue, 11 February 2003 10:30

Rick Towler
Messages: 821
Registered: August 1998

Senior Member

"lyubo" wrote in message ...

> How do I draw a single point in 3D?

AFAIK you can't just plot a single point but you have a few options.

The simplest would be to use IDLgrPolyline along with IDLgrSymbol. Set your
linestyle to 6 (no line) and set the SYMBOL keyword to an instance of
IDLgrSymbol. The built in symbols are 2d, but you can roll your own 3d
symbols. I would assume you can use VERT_COLORS to color the points
accordingly.

> I have to display a large number of points in 3-D and using a polyline
> (or texture mapped polygons) isn't an option. Is there any other way?

Since you need to display a "large" number of points I think polyline is the
only way to go. If you create your own symbol, keep the number of verts as
low as possible. A cube symbol will probably look like a dot at the scale
you will be drawing it at.

The only other option would be using IDLgrPolygon to represent a point. For
a large number of points this is a less than optimum approach as too many
atoms in the graphics tree slow the drawing process considerably.

-Rick

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