<div dir="auto">I don’t know anything about this, but can’t you take the cross product of two vectors (always assuming the same order) to get an up vector?  Is the issue that one needs a single up vector for multiple rotations or vectors?  Could one average all the cross products?</div><div dir="auto"><br></div><div dir="auto">Just onlooking, not really participating.</div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Aug 31, 2024 at 5:15 AM Holger Seelig via x3d-public <<a href="mailto:x3d-public@web3d.org">x3d-public@web3d.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="line-break:after-white-space">It is possible to calculate a rotation from fromVector to toVector, but these rotations have an arbitrary upVector. <div><br></div><div>And yes, it would be better to have a defined upVector to make these rotations stable.</div></div><div style="line-break:after-white-space"><div><div><br></div><div>Holger</div><div><br id="m_2731415745075159130lineBreakAtBeginningOfMessage"><div>
<div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;line-break:after-white-space"><div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;line-break:after-white-space"><div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;line-break:after-white-space"><div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;line-break:after-white-space"><div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;line-break:after-white-space"><div dir="auto" style="text-align:start;text-indent:0px;line-break:after-white-space"><div style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">--</div><div style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">Holger Seelig</div><div style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">Leipzig, Germany</div><div style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><br></div><div style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><a href="mailto:holger.seelig@yahoo.de" target="_blank">holger.seelig@yahoo.de</a></div><div><a href="https://create3000.github.io/x_ite/" target="_blank">https://create3000.github.io/x_ite/</a></div></div></div></div></div></div></div>
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<div><br><blockquote type="cite"><div>Am 30.08.2024 um 23:45 schrieb Patrick Dähne <<a href="mailto:pdaehne@gmail.com" target="_blank">pdaehne@gmail.com</a>>:</div><br><div><div>Unfortunately, it is not possible to implement NurbsOrientationInterpolator because it is not specified how to calculate the „up“ vector (the tangent of the curve only specifies the z axis, but neither the x nor y axis of the local coordinate system). The same applies to any other hypothetical „xOrientationInterpolator“.<br><br>Bye,<br><br>Patrick<br><br></div></div></blockquote></div><br></div></div></div>_______________________________________________<br>
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