I was only assuming item #1. I think preferable important to change size and be
occluded.
> 1. Why is "always faces the viewer" a property of text? Why not just add a
> FaceTheViewer transformation that assures that the coordinate system after
> the FaceTheViewer is aligned with the camera's coordinate system? What if
> there are multiple cameras, either because a stereo projection is being
> performed or because the virtual world is being projected onto multiple
> physical screens (ala the CAVE or big-screen vis sim setups)?
Actually it would be neat to be able to make any object (or subtree)
always face the user, opposed to just text. The problem is that a
transformation that changes with the viewpoint is not something we can
currently encode into the scene. Perhaps a different solution to the
same problem would be to add an fixed_orientation field to the
coordinate3 node, that would render any nodes that inherit from it such
that their orientation remains fixed as the viewpoint changes. This
would work for both 3D text and would be really handy for things ike
floating 3D menus that you want to face the users so their always
pickable.
Len Wanger -- [email protected]
Interactive Simulations Inc.
http://www.intsim.com/~isigen
------
On Tue, 25 Apr 1995, Gavin Bell wrote:
> > >How about a vote on the issue?
> > I'm with Len on this one. Let's put it up to a vote.
>
> I vote no.
>
> The word "annotation" is too vague; are you proposing text that:
>
> 1. always faces the viewer
> 2. is always the same size on any "screen"
> 3. is not occluded by other objects in the world
>
> All of these bring up sticky issues:
>
> 1. Why is "always faces the viewer" a property of text? Why not just add a
> FaceTheViewer transformation that assures that the coordinate system after
> the FaceTheViewer is aligned with the camera's coordinate system? What if
> there are multiple cameras, either because a stereo projection is being
> performed or because the virtual world is being projected onto multiple
> physical screens (ala the CAVE or big-screen vis sim setups)?
>
> 2. Ditto for "always the same size"-- why not a kind of scale node that says
> "I want distance 1.0 in object space to map into a distance of XXX
> millimeters on the screen"?
>
> 3. What should browsers that support stereo views do for objects that aren't
> occluded by other objects? Conflicting depth cues seems like a sure way to
> get a massive headache...