I'm sorry, I used the wrong words. I meant to say, "both are
scene declaration languages"; yes, you can use Yart/Tcl for a scene
description.
Note that Tcl is a procedural, not a declarative language. Some
(including myself) had voiced concern that this could cause
editability, performance, functional, extendability, and security problems.
However, I am trying to understand a bit more, there are some aspects
of Tcl that might be very nice, esp. for behaviours.
> In my eyes such scene language could easyly specificated by:
> - using the Tcl API of the graphics kernel
> - using the class system
> - limiting the use of Tcl to set, for, if, while, ... (i.e. no
> usage of exec, file related commands etc.)
Hmm.
> For objects that need data files for their creation (OFF polygons,
> images, ...) there have to be specified additional mechanisms
> (load path, etc.).
Yes. There have been long discussions of this on the vrml mailing list.
> For YART extensions (scientifc class lib) there could be defined
> related scene description extensions.
>
> >> I do beleive, however, that animated, interacting, multi-presence,
> >> multi-user, distributed vrml integrated with www is possible with either
> >> inventor/weboogl style languages, or with yart/tcl style languages.
> >> The questions are:
> On very important feature of the YART solution is, that you can
> do incremental scene changes via ASCII commands (here Tcl).
> This reduces the network costs drastically.
Yes. Important point.
> E.g.: When a new user logs into the scene or someone changes anything
> in the scene there will be sent Tcl commands to all mirror
> scenes. These are typically less than 1KByte. As I know Inventor
> and other systems can (initially) read a complete scene descrip-
> tion and thats it.
>
> >> And when you do this, be sure to announce to the vrml group.
> Do you know its email address?
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> Bye,
> Ekki
>
> ****************************************************************
> * Ekkehard 'Ekki' Beier *
> * email: ekki@prakinf.tu-ilmenau.de *
> * phone: ++49-3677-691243 fax: ++49-3677-691201 *
> * talk : ekki@metallica.prakinf.tu-ilmenau.de [141.24.11.247] *
> * www : http://metallica.prakinf.tu-ilmenau.de/ekki.html *
> * Technical University of Ilmenau *
> * Department of Computer Graphics *
> * Am Ehrenberg, PSF 327, D-98684 Ilmenau, GERMANY *
> ****************************************************************