Complex manipulation interaction is handled in VRML
too, as I was mentioning. 

They employ special objects: sensors, which kick in
on certain events, for example selecting a handle object,
typically providing visual feedback. Sensors constrain movement
to certain sub-space, such as Plane Sensor would be used
to move pieces on a game board. The sensor processes
the window coordinates and responds with it's local
subspace coordinates. So even if you change position and orientation
of your board, you still get the same relative board coordinates.

If you had a generic 3D cursor, it will still give you unrelated
absolute coordinates, which you will have to match with your objects.

Sensors naturally extend the basic exploratory mapping
of window space to object spaces.

Plus you don't need to learn multi-wheel mouse, or
several sets of keys.

Things, which can help make a successful editor
are gluing and alignment guides, local coordinate vectors
and mesh to give the sense of relativity, position and direction.
You use one hand to activate keyboard modifiers
and the other to move the regular mouse within
corresponding constrained subspace in a predictable way.

Photoshop is a very good example of such interactivity
to do various complex manipulations on 2D canvases.


--- "Miller, Raul D" <[EMAIL PROTECTED]> wrote:

> Zach Reiter wrote:
> > Does the pickcube demo do what you want?
> 
> That would probably work for something as regular as
> a checker board.
> 
> However, it wouldn't work for something more complex.
> 
> For example, if I wanted to write a geometry editor:
> where a person could drag regular solids into the
> opengl scene, then modify them by dragging vertices
> around, gluing vertices, edges or faces together,
> and so on, the approach in the pickcube demo would
> be inadequate.
> 
> -- 
> Raul



__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to