<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Wingdings;
panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
p.m2488993194815170307msolistparagraph, li.m2488993194815170307msolistparagraph, div.m2488993194815170307msolistparagraph
{mso-style-name:m_2488993194815170307msolistparagraph;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:1085300944;
mso-list-template-ids:-1;}
@list l0:level1
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level2
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:1.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level3
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:1.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level4
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:2.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level5
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:2.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level6
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:3.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level7
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:3.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level8
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:4.0in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l0:level9
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:4.5in;
mso-level-number-position:left;
text-indent:-.25in;
mso-ansi-font-size:10.0pt;
font-family:Symbol;}
@list l1
{mso-list-id:1687367560;
mso-list-type:hybrid;
mso-list-template-ids:2000862998 -1 67698691 67698693 67698689 67698691 67698693 67698689 67698691 67698693;}
@list l1:level1
{mso-level-start-at:0;
mso-level-number-format:bullet;
mso-level-text:\F0D8;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Wingdings;
mso-fareast-font-family:"Times New Roman";
mso-bidi-font-family:"Times New Roman";}
@list l1:level2
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:"Courier New";}
@list l1:level3
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Wingdings;}
@list l1:level4
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Symbol;}
@list l1:level5
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:"Courier New";}
@list l1:level6
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Wingdings;}
@list l1:level7
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Symbol;}
@list l1:level8
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:"Courier New";}
@list l1:level9
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Wingdings;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></style></head><body lang=EN-US link=blue vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><ul style='margin-top:0in' type=disc><li class=MsoListParagraph style='margin-left:0in;mso-list:l1 level1 lfo2'>4D vectors in X3D don't hold quaternions. In X3D rotations are in SF/MFRotation given as axis-angle.<o:p></o:p></li></ul><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Yes, thank you. Then why isn’t the default same as for rotation default? </p><p class=MsoNormal><o:p> </o:p></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:michalis.kambi@gmail.com">Michalis Kamburelis</a><br><b>Sent: </b>Monday, March 14, 2022 9:16 PM<br><b>To: </b><a href="mailto:joedwil@earthlink.net">Joseph D Williams</a><br><b>Cc: </b><a href="mailto:yottzumm@gmail.com">John Carlson</a>; <a href="mailto:x3d-public@web3d.org">X3D Public Mailing List (x3d-public@web3d.org)</a><br><b>Subject: </b>Re: [x3d-public] Mantis 1392: 5.3.20 SFVec4d and MFVec4d defaultvalue(0 0 0 1) or (0 0 0 0) ?</p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>4D vectors in X3D don't hold quaternions. In X3D rotations are in SF/MFRotation given as axis-angle.</p></div><div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>W dniu wt., 15.03.2022 o 00:05 Joseph D Williams <<a href="mailto:joedwil@earthlink.net">joedwil@earthlink.net</a>> napisał(a):</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><ul type=disc><li class=m2488993194815170307msolistparagraph style='mso-list:l0 level1 lfo1'>three-dimensional (3D) homogeneous vector </li></ul><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>For safety, default should be a legal quaternion (xyzw add to 1?) then 0 0 0 0 not good but generally 0 0 0 1 should be harmless as a default. I haven’t found all places this is used</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Default rotation is 0 0 1 0 (ready to roll if it gets some angle). Likewise, 0 0 0 1 is legal and ready to do whatever if its gets some xyz data. </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Thanks,</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Joe</p></div></div><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:michalis.kambi@gmail.com" target="_blank">Michalis Kamburelis</a><br><b>Sent: </b>Sunday, March 13, 2022 3:08 PM<br><b>To: </b><a href="mailto:yottzumm@gmail.com" target="_blank">John Carlson</a><br><b>Cc: </b><a href="mailto:x3d-public@web3d.org" target="_blank">X3D Public Mailing List (x3d-public@web3d.org)</a><br><b>Subject: </b>Re: [x3d-public] Mantis 1392: 5.3.20 SFVec4d and MFVec4d defaultvalue (0 0 0 1) or (0 0 0 0) ?</p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The description of 4D vectors states their purpose: "a</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>three-dimensional (3D) homogeneous vector".</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The 4D value "0 0 0 1" means "3D position at (0,0,0), when interpreted</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>as (3D) homogeneous vector".</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The 4D value "0 0 0 0" would mean "invalid value, when interpreted as</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>(3D) homogeneous vector".</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Let's keep the "0 0 0 1" as default. I don't see any reason to change,</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>"0 0 0 1" makes sense. (One could also argue that "0 0 0 0" makes</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>sense, but it is a flip a coin, they both can be argued as "better</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>defaults". So, no reason to break compatibility.)</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Regards,</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Michalis</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>niedz., 13 mar 2022 o 19:48 John Carlson <<a href="mailto:yottzumm@gmail.com" target="_blank">yottzumm@gmail.com</a>> napisał(a):</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> My guess is it has to do with a perspective transformation.</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> John</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> On Sun, Mar 13, 2022 at 1:35 PM Brutzman, Donald (Don) (CIV) <<a href="mailto:brutzman@nps.edu" target="_blank">brutzman@nps.edu</a>> wrote:</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Clause 5.3.20 SFVec4d and MFVec4d lists default value as (0 0 0 1)</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Why not (0 0 0 0) similar to other SFVec/MFVec fields?</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> <a href="https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/fieldTypes.html#SFVec4dAndMFVec4d" target="_blank">https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/fieldTypes.html#SFVec4dAndMFVec4d</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Similarly for 5.3.21 SFVec4f and MFVec4f</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> <a href="https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/fieldTypes.html#SFVec4fAndMFVec4f" target="_blank">https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/fieldTypes.html#SFVec4fAndMFVec4f</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Entered as</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Mantis 1392: 5.3.20 SFVec4d and MFVec4d default value (0 0 0 1) or (0 0 0 0) ?</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> <a href="https://www.web3d.org/member-only/mantis/view.php?id=1392" target="_blank">https://www.web3d.org/member-only/mantis/view.php?id=1392</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> all the best, Don</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> --</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Don Brutzman Naval Postgraduate School, Code USW/Br <a href="mailto:brutzman@nps.edu" target="_blank">brutzman@nps.edu</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA +1.831.656.2149</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> X3D graphics, virtual worlds, Navy robotics https:// <a href="http://faculty.nps.edu/brutzman" target="_blank">faculty.nps.edu/brutzman</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> _______________________________________________</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> x3d-public mailing list</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> <a href="mailto:x3d-public@web3d.org" target="_blank">x3d-public@web3d.org</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>>> <a href="http://web3d.org/mailman/listinfo/x3d-public_web3d.org" target="_blank">http://web3d.org/mailman/listinfo/x3d-public_web3d.org</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> _______________________________________________</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> x3d-public mailing list</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> <a href="mailto:x3d-public@web3d.org" target="_blank">x3d-public@web3d.org</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> <a href="http://web3d.org/mailman/listinfo/x3d-public_web3d.org" target="_blank">http://web3d.org/mailman/listinfo/x3d-public_web3d.org</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>_______________________________________________</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>x3d-public mailing list</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="mailto:x3d-public@web3d.org" target="_blank">x3d-public@web3d.org</a></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="http://web3d.org/mailman/listinfo/x3d-public_web3d.org" target="_blank">http://web3d.org/mailman/listinfo/x3d-public_web3d.org</a></p></div></div></blockquote></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><p class=MsoNormal><o:p> </o:p></p></div></body></html>