| Re: Object Graphics: multiple Views of same model [message #28566 is a reply to message #28562] |
Tue, 18 December 2001 06:34   |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Martin Downing (martin.downing@ntlworld.com) writes:
> Ok, todays object graphics question:
> Say you have a 3D object model and you want to view it in 2 or 3 orthogonal
> directions as you rotate/manipulate it.
> Can this be done with a single object instance? Which we would represent :
>
> grObject
> |
> IDLgrModel_Group
> | |
> IDLgrModel_Transform1 IDLgrModel_Transform2
> | |
> View1 View2
>
> I guess not as we now have the reverse of IDLs graphics Hierarchy, and our
> model_group is not allowed two parents (poor thing!). However it seems to me
> a very reasonable thing to want to do, as a graphics model should be
> viewable from multiple positions. I cant see how Scenes or Viewgroups can
> help, so is the only way to use one view, switching all its settings and the
> top level model transform to look like other views before drawing to the
> other windows?
I didn't mean to insult you the other day, Martin.
I know perfectly well you know what you are doing with
3D graphics, but sometimes I like to overemphasize the
point for our readers. :-)
If I wanted to see two or more views of the same
polygon object, I think I would start by create
two or more polygon objects that all shared the
same data (with the SHARE_DATA keyword). Each
object could go into its own model, each model
into its own view, and the views could be
collected into a scene, that I would display
in my window.
This scheme allows you to manipulate the models
independently to get two or more views of the
same polygon dataset.
I have to admit, I've never had occasion to
use the shared data trick, but it seems to me
the application you describe is exactly why
it is there.
Cheers,
David
--
David W. Fanning, Ph.D.
Fanning Software Consulting
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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