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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Hi Alessandro,</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> I'm not sure I understand your question and I don't know Google SketchUp, but if you know which edges should form your line loop and you know the starting and ending vertex number for each of these edges, then it should be quite simple: </p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> 1) pick the first edge from a loop</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> 2) the following edge must be such that its starting vertex number is the same as the ending vertex number of the previous edge. If that's not the case, add the new edge in the for loop with a minus sign (i.e. flip it)</p>
<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> Here I suppose that the new edge you're adding has at least one vertex common with the prevous edge</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> 3) if there are any edges left to process (the loop is still not closed), repeat 2)</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> I don't know if the edges coming from SketchUp are already ordered and they're just not oriented, or if they are not ordered at all. In the latter case, you'll have to modify step 2) to search for suitable candidate edges every time you want to increment your line loop.</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> Best regards,</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;"> Martin Vymazal</p>
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<p style=" margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">On Friday 21 of September 2012 12:07:38 Alessandro Barracco wrote:<br /></p>
<p style=" margin-top:12px; margin-bottom:12px; margin-left:40px; margin-right:40px; -qt-block-indent:0; text-indent:0px; -qt-user-state:0;">Hi all, I'm writing a Google SkecthUp plugin that export geometry into the *.geo format. I'm able to export vertices, edges and, partially, the line loops. But I don't know how to choose the right sign for all the edges that form a loop: to be much clear, I need an algorithm that help me to understand when the edge orientation agrees with the choosed <a name="result_box"></a>direction of travel into the loop. Any suggestion?</p>
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