[x3d-public] candidate feature: display bounding box

Andreas Plesch andreasplesch at gmail.com
Tue Jan 21 05:39:05 PST 2020

Since the appearance of the shown bbox cannot be controlled and would be up
to the browser, the feature would be mostly for debugging during authoring.
So I think for X3D browsers it is not critical.
An implementation issue is that browsers would typically organize rendering
around Shapes but a X3DBoundedObject such as Group does not necessarily
need to contain a Shape.
So I think it would not become a priority for x3dom. InstantReality already
has the field, however, so the two implementations may not be out reach if
the feature is standardized.

---on the phone---

On Mon, Jan 20, 2020, 9:20 PM Don Brutzman <brutzman at nps.edu> wrote:

> Summary: we should consider adding a field on X3DBoundedObject nodes to
> display bounding boxes.
> On 1/18/2020 7:04 AM, Andreas Plesch wrote:
> > It makes a lot of sense to use X3DBoundedObject for a visible field.
> > It turns out that x3dom always used X3DBoundedObject for its render
> field:
> >
> >
> https://github.com/x3dom/x3dom/blob/master/src/nodes/Grouping/X3DBoundedObject.js#L40
> >
> > x3dom  followed InstantReality:
> >
> > https://doc.instantreality.org/documentation/nodetype/BoundedNode/
> namely "showBBox        SFBool  inputOutput     FALSE           Show
> Bounding Box of Subtree."
> Bounding boxes may optionally be provided by authors but are almost always
> computed directly by browsers.
> This feature is also provided in view3dscene and other tools, albeit
> perhaps as a browser setting.
> The ability to display bounding boxes has multiple potential benefits:
> - highlight geometry of interest, such as a selection or a target;
> - show collision boundaries, for camera-to-object or object-to-object
> collisions;
> - provide highlighted user feedback,
> - ... other uses perhaps?
> This feature can be accomplished by authors but only with significant
> effort, complex error-prone computation, and higher profiles for use of
> scripting (and likely prototypes as) well.
> I doubt if an X3D player can implement X3D without having this feature
> already.
> Suggested specification addition:
> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/group.html#X3DBoundedObject
> 10.3.1 X3DBoundedObject
>         SFBool [in out] showBBox FALSE
> "When showBBox is true, a wireframe bounding box is displayed for the
> associated geometry."
> All opinions and improvements welcome.
> all the best, Don
> --
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
> X3D graphics, virtual worlds, navy robotics
> http://faculty.nps.edu/brutzman
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