[x3d-public] X3DParticleEmitter node inherit fromX3DChildNode(ratherthan X3DNode)

[Andreas Plesch]

Hi Joe,

I am not an svg expert but this found out:

>
> Ø   <use x="5" y="5" href="#myCircle" fill="url('#myGradient')" />
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> OK, but why the use uses href and url names when the objective is the same, just to reference the defs id values?

href points the def name, and fill needs an url for gradients as
'paint servers':
https://www.w3.org/TR/SVG/painting.html#SpecifyingPaint
That is just how svg is specified.

> Can you change the values in the defs?

Yes. I just experimentally confirmed that changing the defs is
reflected in the use. Not sure where in the spec. to look but probably
well defined somewhere.

Cheers, Andreas

>
> Joe
>
>
>
> <svg viewBox="0 0 10 10" xmlns="http://www.w3.org/2000/svg">
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>   <!-- Some graphical objects to use -->
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>   <defs>
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>     <circle id="myCircle" cx="0" cy="0" r="5" />
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>
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>     <linearGradient id="myGradient" gradientTransform="rotate(90)">
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>       <stop offset="20%" stop-color="gold" />
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>       <stop offset="90%" stop-color="red" />
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>     </linearGradient>
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>   </defs>
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>
>
>   <!-- using my graphical objects -->
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>   <use x="5" y="5" href="#myCircle" fill="url('#myGradient')" />
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> </svg>
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>
>
> From: Andreas Plesch
> Sent: Friday, March 11, 2022 7:32 AM
> To: Brutzman, Donald (Don) (CIV)
> Cc: Joseph D Williams; X3D Graphics public mailing list; Jakub Flotyński
> Subject: Re: [x3d-public] X3DParticleEmitter node inherit fromX3DChildNode(ratherthan X3DNode)
>
>
>
> On Thu, Mar 10, 2022 at 9:41 PM Brutzman, Donald (Don) (CIV) <brutzman at nps.edu> wrote:
>
> Sorry I thought we were talking about Metadata examples, not DEF/USE id/idref identifier/copy-by-reference kinds of reuse.
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>
>
> glTF and collada have "extras" for unstructured metadata. glTF now also has structured metadata:
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> https://www.khronos.org/blog/pervasive-asset-metadata-in-3dcommerce
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> based on the XMP standard.
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> https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_xmp_json_ld
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> has the details.
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>
>
> To avoid further confusion, let me emphasize this is completely unrelated to library node functionality.
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>
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> Hope this helps, Andreas
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>



-- 
Andreas Plesch
Waltham, MA 02453