[x3d-public] add 'hidden' field to Shape?

[Holger Seelig]

I agree with the opinion that the field should be available as well on 
X3DShapeNode and X3DGroupingNode, but I think the logic should be 
reversed: TRUE should mean ON/visible, and FALSE should mean OFF/hidden. 
Better name the field 'visible' or even like X3DOM 'render'. Think about 
interconnectivity, routing from one exiting field to the new 
X3DShapeNode field, you could route a TimeSensor's isActive or isPaused 
fields, or a TouchSensor's isActive or isOver fields directly to the new 
field if the logic is like above, to display for instance a 'lamp' shape 
to indicate the action. This would not be possible if the field is named 
'hidden' some logic would be need to negate the logic: 
TimeSensor.isActive -> NOTScript -> Shape.hidden. With the logic above, 
no Script node is needed.

Best regards,
Holger


On 13.12.19 12:17, vmarchetti at kshell.com wrote:
> 1. There is a extension attribute in X3DOM called the 'render' 
> attribute which serves this purpose, with opposite parity (meaning 
> render=true has the same effect as hidden=false). It is higher up in 
> the X3DOM inheritance tree, (see 
> https://doc.x3dom.org/author/Grouping/X3DBoundedObject.html ) so it is 
> an attribute in both the ShapeNode and the grouping nodes.
>
> 2. To add this field to Shape, and potentially the grouping nodes, we 
> would need to specify how it behaves when the Shape node is referenced 
> multiple times in a Scene with DEF/USE statements. This is a common 
> pattern when a Shape is something which is repeated multiple times, 
> think tires on a car. However, if 'hidden' is defined as a field on 
> the Shape then all the tires would be shown/hidden together, which may 
> not be the desired effect. If the authoring solution to avoid this is 
> to enclose each tire in its own Group node and apply hidden on that 
> Group, then you're pretty much back to the existing design pattern 
> available with the Switch node.
>
> Vince Marchetti
>
>> On Dec 12, 2019, at 11:23 AM, Don Brutzman <brutzman at nps.edu 
>> <mailto:brutzman at nps.edu>> wrote:
>>
>> A common task in 3D graphics is selectively hiding geometry.
>>
>> X3D is fairly clumsy about this, typically requiring Switch or LOD 
>> animation to achieve it.
>>
>> HTML has a much simpler approach, the 'hidden' attribute.  There is a 
>> similar construct in CSS.
>>
>> HTML5 6.1 The hidden attribute
>> https://html.spec.whatwg.org/multipage/interaction.html#the-hidden-attribute
>>
>> As a similar way to simplify hidding, either for pure X3D or hybrid 
>> html/X3D, wondering if we might add a 'hidden' attribute to Shape.
>>
>> 12.4.6 Shape
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD1/Part01/components/shape.html#Shape
>>
>> SFBool [in out] hidden FALSE
>>
>> Might we add hidden to Shape?  Is there a better approach?
>>
>> 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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-- 
Holger Seelig
Digital Media Designer

Scheffelstraße 31a
04277 Leipzig
Germany

Cellular: +49 176 420 479 37
E-Mail:   holger.seelig at create3000.de
Web:      http://create3000.de

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