[x3d-public] X3D minutes 20 MAR 2020: X3DChildNode implementing X3DBoundedObject

Sun Apr 5 13:12:06 PDT 2020

> Message: 1
> Date: Sat, 4 Apr 2020 18:34:56 -0700
> From: Don Brutzman <brutzman at nps.edu>
> To: X3D Graphics public mailing list <x3d-public at web3d.org>
> Subject: Re: [x3d-public] X3D minutes 20 MAR 2020: X3DChildNode
>         implementing X3DBoundedObject
>
> I think you are correct that nodes which have X3DBoundedObject also have X3DChildNode.
>
> Tried to apply this change: X3DChildNode implementing X3DBoundedObject interface.  (The other way around doesn't work, abstract interfaces can't implement abstract types).

I probably did not appreciate the difference between abstract
interface (to me, an interface definition which can be used by a
(abstract) node definition) and an abstract type (to me, a node type
which can be used to define/be implemented by a concrete, actual
node). There seemed to be redundancy since (almost) all nodes which
have the X3DBoundedObject interface, are child nodes. So, informally,
it seemed possible to say only once "X3DBoundedObject means
additionally child node", and then only refer to the X3DBoundedObject
(interface) in the node signature/definition.

>
> However this change is not really possible: many nodes implement X3DChildNode but do not have X3DBoundedObject interfaces (BooleanFilter, BooleanToggle, ClipPlane etc. etc.)  See summary diagram (subtree under X3DChildNode) at
>
> * Figure 4.2 ? Interface hierarchy
>    https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/concepts.html#f-Objecthierarchy

Agreed, the other round (of course) does not work.

> Documented this possibility in following new issue, then closed it.
>
> * Mantis 1289: X3DChildNode implementing X3DBoundedObject interface
>    https://www.web3d.org/member-only/mantis/view.php?id=1289
>
> In passing, also found that some specification interface descriptions incorrectly refer to themselves as abstract node types which is incorrect (e.g. 10.3.1 X3DBoundedObject). Ensure all X3D*Object abstract interface definitions use correct nomenclature.  Entered issue 1288.
>
> * Mantis 1288: ensure abstract interfaces are not referred to as abstract node types
>    https://www.web3d.org/member-only/mantis/view.php?id=1288
>
> "Fixed specification prose for X3DBoundedObject, X3DFogObject, X3DPickableObject and X3DProgrammableShaderObject."

I think that will be helpful. Perhaps it requires explaining what an
abstract interface is.

Thanks for looking into this,

-Andreas

> On 3/21/2020 5:13 PM, Don Brutzman wrote:
> > Another issue, but we didn't have time to discuss today.? TODO further specification review and X3D unified object model checks.
> >
> >> [7] [x3d-public] X3DBoundedObject always X3DChildNode ?
> >> https://web3d.org/pipermail/x3d-public_web3d.org/2020-February/011787.html
> >>
> >> "Ignoring for second the exception, I think that means there is a opportunity for simplification of the hierarchy by requiring X3DBoundedObject to implement X3DChildNode."
>
> Full message:
> =============
> Nodes which implement X3DBoundedObject also implement X3DChildNode,
> except for one node:
> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/concepts.html#f-Objecthierarchy
>
> Ignoring for second the exception, I think that means there is a opportunity for simplification of the hierarchy by requiring X3DBoundedObject to implement X3DChildNode.
>
> The exception is X3DNBodyCollisionSpaceNode (X3DBoundedObject)* -+-
> CollisionSpace .
>
> It seems curious that CollisionSpace is special. Could CollisionSpace
> become a X3DChildNode ? It seems carefully defined not to be able to
> participate in a Grouping but why ?
>
> Refs:
>
> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/concepts.html#f-Objecthierarchy
> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/rigid_physics.html#CollisionSpace
> =============
>
> >> Thanks Andreas!
> >>
> >> More there, certainly seems worth following up.? We agreed it was worth further consideration, might possibly also resolve issue 1275.
> >>
> >> [7.1] Mantis 1282: is X3DBoundedObject always X3DChildNode ?
> >> https://www.web3d.org/member-only/mantis/view.php?id=1282
>
> As before, thanks for this interesting change suggestion.
>
> 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
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 5 Apr 2020 10:30:39 -0700
> From: Don Brutzman <brutzman at nps.edu>
> To: X3D Graphics public mailing list <x3d-public at web3d.org>
> Subject: [x3d-public] default behavior and headlight if no
>         NavigationInfo appears in a scene
> Message-ID: <cb243569-3dbc-823b-c0fd-7ca2236ed4ea at nps.edu>
> Content-Type: text/plain; charset="utf-8"; format=flowed
>
> Am looking but not finding.  Does X3D specification define default behavior and headlight if no NavigationInfo appears in a scene?
>
> * X3Dv3.3 Navigation component, 23.2 Concepts
>    https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/navigation.html#Concepts
>
> * X3Dv3.3 NavigationInfo
>    https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/navigation.html#NavigationInfo
>
> * X3Dv3.3 Core component, 7.2.2 Bindable children nodes
>    https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/core.html#BindableChildrenNodes
>
> If yes then great, TIA for all help.
>
> If not then we should define expectations together and add this to X3D4.
>
> 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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-- 
Andreas Plesch
Waltham, MA 02453