<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">You can discretize straight line segments into arbitrarily small pieces and project them onto the surface.</div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">

<br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">If you are replying to me, please add my email in the to or cc fields so I get it directly in my inbox. I do not check mailing lists every day.</div>


<div class="gmail_extra">
<br><br><div class="gmail_quote">On Sat, Nov 30, 2013 at 6:06 AM, Green Hedgehog <span dir="ltr">&lt;<a href="mailto:yy198903@163.com" target="_blank">yy198903@163.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">



<div style="line-height:1.7;font-size:14px;font-family:arial">Dear Dženan Zukić,<div>Thanks a lot for your reply. The key point is, how to connnect the projected points. I mean, how to guarantee the short lines connecting projected points lying on the surface?<div>



<br><br><br><br><br><div></div><div></div><br>At 2013-11-29 19:15:56,&quot;Dženan Zukić [via VTK]&quot; &lt;<a href="http://user/SendEmail.jtp?type=node&amp;node=5724732&amp;i=0" rel="nofollow" link="external" target="_blank">[hidden email]</a>&gt; wrote:<br>



 </div><blockquote style="border-left:2px solid #cccccc;padding:0 1em"><div><div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">If your curve is a loop, you might want to do spherical projection. Determine center of area of the curve. Then go through all the points in your curve, for each cast a ray from center towards it, calculate intersection of this ray with the surface and place the projected point on this intersection. Lastly connect the projected points.</div>





<div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small">In case your curve and the surface are not concentric, you might want to place the center of projection somewhere between them so the projection ends up on the surface.</div>





</div></div><div><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Nov 28, 2013 at 1:24 PM, Green Hedgehog <span dir="ltr">&lt;<a href="http://user/SendEmail.jtp?type=node&amp;node=5724721&amp;i=0" rel="nofollow" link="external" target="_blank">[hidden email]</a>&gt;</span> wrote:<br>





<blockquote style="border-left:2px solid #cccccc;padding:0 1em" class="gmail_quote"><div style="line-height:1.7;font-size:14px;font-family:arial">Dear Kenneth,<div>Thanks a lot for your reply. I think I didn&#39;t describe the question clearly. </div>





<div>a) The curve isn&#39;t planar. It isn&#39;t close to planar neither. It is a loop, an output of vtkSplineFilter.</div><div>b) The surface isn&#39;t close to planar near the curve.</div><div>c) I didn&#39;t get you quite well about this point. I mean I want the result just looks like you draw the curve on the surface, that means after projecting the result curve is totally <i>lying </i>on the surface. It needn&#39;t be accurate, just looks smooth.</div>





<div><br></div><div>Regards,</div><div>Yue<div><br> <br><br><br><br><div></div><div></div><br>At 2013-11-28 14:39:54,&quot;Kenneth Sloan-3 [via VTK]&quot; &lt;<a href="http://user/SendEmail.jtp?type=node&amp;node=5724694&amp;i=0" rel="nofollow" link="external" target="_blank">[hidden email]</a>&gt; wrote:<br>





 </div><blockquote style="border-left:2px solid #cccccc;padding:0 1em"><div>

        A lot depends on the nature of the curve and the surface.
<br><br>a) is the curve (close to) planar?
<br>b) is the surface close to planar near the curve?
<br>c) do you want the curve literally &quot;projected&quot; onto the surface, or do want
<br>   the curve somehow &quot;draped&quot; over the surface?
<br><br>Easiest is probably the case where the surface is large and locally &quot;flat&quot; near the curve, and the curve
<br>itself is relatively flat.  Select a compromise plane (or, from another point of view, a compromise vector from the curve in the direction of the surface).  Sample the curve, and cast rays from curve sample points in the direction of the surface.  Find points of intersection and connect the dots.
<br><br>If both the surface and the curve are convoluted, then the problem becomes much harder, and the answer less well defined.
<br><br>Good luck!
<br>--
<br>Kenneth Sloan
<br></div><a href="http://user/SendEmail.jtp?type=node&amp;node=5724691&amp;i=0" rel="nofollow" link="external" target="_blank">[hidden email]</a>
<br><div><br><br>On Nov 28, 2013, at 05:49 , Green Hedgehog &lt;<a href="http://user/SendEmail.jtp?type=node&amp;node=5724691&amp;i=1" rel="nofollow" link="external" target="_blank">[hidden email]</a>&gt; wrote:
<br><div><div><div><div><br>&gt; Dear all,
<br>&gt; 
<br>&gt; There is a closed surface with a curve near it. I want to project the curve
<br>&gt; onto the surface and then render . Does anyone have any suggestions?
<br>&gt; 
<br>&gt; Yue
<br>&gt; 
<br>&gt; 
<br>&gt; 
<br>&gt; --
<br>&gt; View this message in context: <a href="http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690.html" rel="nofollow" link="external" target="_blank">http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690.html</a></div>





&gt; Sent from the VTK - Users mailing list archive at Nabble.com.
<br>&gt; _______________________________________________
<br>&gt; Powered by <a href="http://www.kitware.com" rel="nofollow" link="external" target="_blank">www.kitware.com</a>
<br>&gt; 
<br>&gt; Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" rel="nofollow" link="external" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>&gt; 
<br>&gt; Please keep messages on-topic and check the VTK FAQ at: <a href="http://www.vtk.org/Wiki/VTK_FAQ" rel="nofollow" link="external" target="_blank">http://www.vtk.org/Wiki/VTK_FAQ</a><br>&gt; 
<br>&gt; Follow this link to subscribe/unsubscribe:
<br>&gt; <a href="http://www.vtk.org/mailman/listinfo/vtkusers" rel="nofollow" link="external" target="_blank">http://www.vtk.org/mailman/listinfo/vtkusers</a></div></div>_______________________________________________
</div>Powered by <a href="http://www.kitware.com" rel="nofollow" link="external" target="_blank">www.kitware.com</a>
<br><br>Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" rel="nofollow" link="external" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br><br>





Please keep messages on-topic and check the VTK FAQ at: <a href="http://www.vtk.org/Wiki/VTK_FAQ" rel="nofollow" link="external" target="_blank">http://www.vtk.org/Wiki/VTK_FAQ</a><br><br>Follow this link to subscribe/unsubscribe:
<br><a href="http://www.vtk.org/mailman/listinfo/vtkusers" rel="nofollow" link="external" target="_blank">http://www.vtk.org/mailman/listinfo/vtkusers</a><br>

        
        
        
        <br>
        <br>
        </div><hr noshade size="1" color="#cccccc">
        <div style="color:#444;font:12px tahoma,geneva,helvetica,arial,sans-serif">
                <div style="font-weight:bold">If you reply to this email, your message will be added to the discussion below:</div>
                <a href="http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690p5724691.html" rel="nofollow" link="external" target="_blank">http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690p5724691.html</a>
        </div>
        <div style="color:#666;font:11px tahoma,geneva,helvetica,arial,sans-serif;margin-top:.4em;line-height:1.5em">
                
                To unsubscribe from How to project a curve onto surface, <a rel="nofollow" link="external">click here</a>.<br>
                <a href="http://vtk.1045678.n5.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&amp;id=instant_html%21nabble%3Aemail.naml&amp;base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&amp;breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" rel="nofollow" style="font:9px serif" link="external" target="_blank">NAML</a>
        </div></blockquote></div></div><br><br><span title="neteasefooter"><span></span></span>

        
        
        
<br><hr align="left" width="300">
View this message in context: <a href="http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690p5724694.html" rel="nofollow" link="external" target="_blank">Re:Re: How to project a curve onto surface</a><div>



<div>

<br>
Sent from the <a href="http://vtk.1045678.n5.nabble.com/VTK-Users-f1224199.html" rel="nofollow" link="external" target="_blank">VTK - Users mailing list archive</a> at Nabble.com.<br></div></div><br>_______________________________________________<br>




Powered by <a href="http://www.kitware.com" rel="nofollow" link="external" target="_blank">www.kitware.com</a><br>
<br>
Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" rel="nofollow" link="external" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>
<br>
Please keep messages on-topic and check the VTK FAQ at: <a href="http://www.vtk.org/Wiki/VTK_FAQ" rel="nofollow" link="external" target="_blank">http://www.vtk.org/Wiki/VTK_FAQ</a><br>
<br>
Follow this link to subscribe/unsubscribe:<br>
<a href="http://www.vtk.org/mailman/listinfo/vtkusers" rel="nofollow" link="external" target="_blank">http://www.vtk.org/mailman/listinfo/vtkusers</a><br>
<br></blockquote></div><br></div>
<br>_______________________________________________
<br>Powered by <a href="http://www.kitware.com" target="_blank">www.kitware.com</a>
<br><br>Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" rel="nofollow" link="external" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br><br>



Please keep messages on-topic and check the VTK FAQ at: <a href="http://www.vtk.org/Wiki/VTK_FAQ" rel="nofollow" link="external" target="_blank">http://www.vtk.org/Wiki/VTK_FAQ</a><br><br>Follow this link to subscribe/unsubscribe:
<br><a href="http://www.vtk.org/mailman/listinfo/vtkusers" rel="nofollow" link="external" target="_blank">http://www.vtk.org/mailman/listinfo/vtkusers</a><br>

        
        
        
        <br>
        <br>
        <hr noshade size="1" color="#cccccc">
        </div></div><div style="color:#444;font:12px tahoma,geneva,helvetica,arial,sans-serif"><div><div>
                <div style="font-weight:bold">If you reply to this email, your message will be added to the discussion below:</div>
                </div></div><a href="http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690p5724721.html" rel="nofollow" link="external" target="_blank">http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690p5724721.html</a>
        </div><div>
        <div style="color:#666;font:11px tahoma,geneva,helvetica,arial,sans-serif;margin-top:.4em;line-height:1.5em">
                
                To unsubscribe from How to project a curve onto surface, <a rel="nofollow" link="external">click here</a>.<br>
                <a href="http://vtk.1045678.n5.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&amp;id=instant_html%21nabble%3Aemail.naml&amp;base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&amp;breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" rel="nofollow" style="font:9px serif" link="external" target="_blank">NAML</a>
        </div></div></blockquote></div></div><div><div><br><br><span title="neteasefooter"><span></span></span>

        
        
        
<br><hr align="left" width="300">
View this message in context: <a href="http://vtk.1045678.n5.nabble.com/How-to-project-a-curve-onto-surface-tp5724690p5724732.html" target="_blank">Re:Re: How to project a curve onto surface</a><br>
Sent from the <a href="http://vtk.1045678.n5.nabble.com/VTK-Users-f1224199.html" target="_blank">VTK - Users mailing list archive</a> at Nabble.com.<br></div></div><br>_______________________________________________<br>
Powered by <a href="http://www.kitware.com" target="_blank">www.kitware.com</a><br>
<br>
Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>
<br>
Please keep messages on-topic and check the VTK FAQ at: <a href="http://www.vtk.org/Wiki/VTK_FAQ" target="_blank">http://www.vtk.org/Wiki/VTK_FAQ</a><br>
<br>
Follow this link to subscribe/unsubscribe:<br>
<a href="http://www.vtk.org/mailman/listinfo/vtkusers" target="_blank">http://www.vtk.org/mailman/listinfo/vtkusers</a><br>
<br></blockquote></div><br></div></div>