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--></style></head><body lang=EN-US link=blue vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><o:p> </o:p></p><ul style='margin-top:0in' type=disc><li class=MsoListParagraph style='margin-left:0in;mso-list:l1 level1 lfo2'>decision was deliberate but cannot speak to the specific motivation</li></ul><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>can be a structure where the meta describes the environment and then encloses some user code. Usefull in the authoring environment as filter for structure and values? In both we strip the meta to get the user code runtime, just that in X3D the meta is info about the containing node that may be useful at import but has no bearing at runtime. Also, I can just imagine reading the stuff if every node could have a meta dad. Maybe the only exception is for a scene root level meta to hold the scene and contain all the search code works for the particular root node or other context. For example this would replace or encase the lines of name-value pairs in the head,.</p><p class=MsoNormal>Thanks </p><p class=MsoNormal>Joe</p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='border:none;padding:0in'><b>From: </b><a href="mailto:andreasplesch@gmail.com">Andreas Plesch</a><br><b>Sent: </b>Thursday, March 10, 2022 1:08 PM<br><b>To: </b><a href="mailto:joedwil@earthlink.net">Joseph D Williams</a><br><b>Cc: </b><a href="mailto:brutzman@nps.edu">Brutzman, Donald (Don) (CIV)</a>; <a href="mailto:x3d-public@web3d.org">X3D Graphics public mailing list</a><br><b>Subject: </b>Re: [x3d-public] X3DParticleEmitter node inherit fromX3DChildNode(ratherthan X3DNode)</p></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>Good comments.</p></div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><ul type=disc><li class=gmail-m-8356456586784332503msolistparagraph style='mso-list:l0 level1 lfo1'>MetadataSet to have X3DNode nodes </li></ul><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>If I understand it, the idea of ending meta to include actual user code for the scenegraph is exactly the sort of extension wanting to be “worthwhile to deviate a bit and be more permissive than the spec” that dooms the long-term validation operation. Maybe good for something with simple structure that looks convenient and logical and seemingly convenient to implement at first thought and elementary usage, then ends up making something definitely not to be best practice. Please delineate the “worthwhile” parts that make a case.</p></div></div></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I only know that this construction shows up in most of x-ite examples, and is how the Titania editor saves a scene, simple or complex. I can only deduce that this decision was deliberate but cannot speak to the specific motivation by the author. Speculating, the feature seems to be valuable for authoring. It should be possible to convert to standard x3d automatically by moving the DEF node from the MetadataSet to the first USE node, perhaps by xslt.</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Not quite sure how validation would be affected.</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><p class=MsoNormal>I agree that Metadata nodes should be limited to actual metadata but a library node seems sensible.</p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal>Here is a list of other, well established scene graph systems which do have a concept of a non-renderable library which is separate and can then be referenced as needed:</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>- svg</p></div><div><p class=MsoNormal>- glTF</p></div><div><p class=MsoNormal>- a-frame</p></div><div><p class=MsoNormal>- collada (I believe)</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>it is a natural concept and perhaps allows for cleaner user code organization. Having two alternative ways to define a DEF node (in a library, and as a first scene graph node) does seem to invite friction, and would need to be carefully considered.</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Andreas</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>From: </b><a href="mailto:andreasplesch@gmail.com" target="_blank">Andreas Plesch</a><br><b>Sent: </b>Tuesday, March 8, 2022 11:39 AM<br><b>To: </b><a href="mailto:brutzman@nps.edu" target="_blank">Brutzman, Donald (Don) (CIV)</a><br><b>Cc: </b><a href="mailto:x3d-public@web3d.org" target="_blank">X3D Graphics public mailing list</a><br><b>Subject: </b>Re: [x3d-public] X3DParticleEmitter node inherit fromX3DChildNode(rather than X3DNode)</p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Yes, I am pretty sure Holger is aware. I only brought it up because Titania/x-ite typically stays very close to the spec. But this is a capability where Titania/x-ite found it worthwhile to deviate a bit and be more permissive than the spec. This decision may point to the value of having a way to DEF any X3DNode (not just child nodes) outside of the scene graph, outweighing strict compliance.</p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>All the best, Andreas</p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>On Tue, Mar 8, 2022 at 2:22 PM Brutzman, Donald (Don) (CIV) <<a href="mailto:brutzman@nps.edu" target="_blank">brutzman@nps.edu</a>> wrote:</p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>MetadataSet is only allowed to contain other Metadata* nodes or comments. Other content will fail validation (and will not load or import in the X3DJSAIL Java and X3DPSAIL Python libraries).</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>The right way to cache non-rendered content for DEF/USE libraries is to put them as children nodes within a Switch node with whichChoice=’-1’.</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><span style='font-size:10.0pt;font-family:"Courier New"'>all the best, Don</span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><span style='font-size:10.0pt;font-family:"Courier New"'>-- </span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><span style='font-size:10.0pt;font-family:"Courier New"'>Don Brutzman Naval Postgraduate School, Code USW/Br <a href="mailto:brutzman@nps.edu" target="_blank">brutzman@nps.edu</a></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><span style='font-size:10.0pt;font-family:"Courier New"'>Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA +1.831.656.2149</span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><span style='font-size:10.0pt;font-family:"Courier New"'>X3D graphics, virtual worlds, Navy robotics https://</span> <span style='font-size:10.0pt;font-family:"Courier New"'><a href="http://faculty.nps.edu/brutzman" target="_blank">faculty.nps.edu/brutzman</a></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><b>From:</b> x3d-public <<a href="mailto:x3d-public-bounces@web3d.org" target="_blank">x3d-public-bounces@web3d.org</a>> <b>On Behalf Of </b>Andreas Plesch<br><b>Sent:</b> Tuesday, March 8, 2022 10:11 AM<br><b>To:</b> X3D Graphics public mailing list <<a href="mailto:x3d-public@web3d.org" target="_blank">x3d-public@web3d.org</a>><br><b>Subject:</b> Re: [x3d-public] X3DParticleEmitter node inherit from X3DChildNode(rather than X3DNode)</p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Of note is that Titania and x-ite allow MetadataSet to have X3DNode nodes, eg. any node, in the value field, not just X3DMetadataObject nodes.</p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>This allows MetadataSet to be used as a NodesLibrary for DEF/USE purposes. In fact, this kind of redirection is the default setup for scenes created in Titania.</p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>SVG also has a NodesLibrary equivalent, the <defs> element:</p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><a href="https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FWeb%2FSVG%2FElement%2Fdefs&data=04%7C01%7Cbrutzman%40nps.edu%7Ca7f1e8503b27409f46ec08da012f296e%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C637823599562085821%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=I%2BYZml0d07AjdVyR0CgxDMmSD5mNZT34TxYWHbxBMhI%3D&reserved=0" target="_blank">https://developer.mozilla.org/en-US/docs/Web/SVG/Element/defs</a></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>-Andreas</p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p></div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt;margin-left:9.6pt'>Date: Mon, 7 Mar 2022 21:29:41 +0100<br>From: Michalis Kamburelis <<a href="mailto:michalis.kambi@gmail.com" target="_blank">michalis.kambi@gmail.com</a>><br>To: Joseph D Williams <<a href="mailto:joedwil@earthlink.net" target="_blank">joedwil@earthlink.net</a>><br>Cc: GPU Group <<a href="mailto:gpugroup@gmail.com" target="_blank">gpugroup@gmail.com</a>>, "X3D Public Mailing List<br> (<a href="mailto:x3d-public@web3d.org" target="_blank">x3d-public@web3d.org</a>)" <<a href="mailto:x3d-public@web3d.org" target="_blank">x3d-public@web3d.org</a>><br>Subject: Re: [x3d-public] X3DParticleEmitter node inherit from<br> X3DChildNode(rather than X3DNode)<br>Message-ID:<br> <<a href="mailto:CAKzBGZNToR-7CmaUzRxBE3xx9J6j2mPgmvKAjQKpGQxjdY_0hA@mail.gmail.com" target="_blank">CAKzBGZNToR-7CmaUzRxBE3xx9J6j2mPgmvKAjQKpGQxjdY_0hA@mail.gmail.com</a>><br>Content-Type: text/plain; charset="UTF-8"<br><br>Perhaps I should have written<br><br>"""<br>The nodes within NodesLibrary don't make any effect, they are not<br>traversed. They are only to be reUSEd (referenced) by other parts of<br>the graph."<br>"""<br><br>This makes the wording consistent with how e.g. Switch is described.<br>Sure you have all the nodes in memory, you just don't traverse to<br>inactive parts of Switch, LOD, NodesLibrary etc.<br><br>Regards,<br>Michalis</p></blockquote></div></div></div></div></blockquote></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><br clear=all></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>-- </p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Andreas Plesch<br>Waltham, MA 02453</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p></div></div></blockquote></div><p class=MsoNormal><br clear=all></p><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>-- </p></div><p class=MsoNormal>Andreas Plesch<br>Waltham, MA 02453</p><p class=MsoNormal><o:p> </o:p></p></div></body></html>