Hi guys,<br><br>I has completely missed this point. I thought the fact that the polygon being closed is the only requirement.<br><br>Is there a filter in VTK that will order a given set of points in the given direction?<br>
<br>Cheers and thanks,<br>Anja<br><br><div><span class="gmail_quote">On 31/10/06, <b class="gmail_sendername">David Gobbi</b> <<a href="mailto:dgobbi@atamai.com">dgobbi@atamai.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Anja,<br><br>The vtkPolyDataToImageStencil calculates the normal of each polygon to<br>find out which face of the polygon is the front (the "outside") and<br>which is the back (the "inside"). The calculation of the normal depends
<br>on the ordering of the points.<br><br>You are extruding a polyline to create the the polydata, right?<br>Unfortunately, I don't whether the the front/back orientation of the<br>polygons depends on the ordering of points in the original polyline...
<br>Dean might have more experience here.<br><br>When you apply the stencil, most classes that have a SetStencil() method<br>also have a ReverseStencilOn() method to set whether you want to use the<br>region inside the stencil or the region outside the stencil.
<br><br> - David<br><br><br>Anja Ende wrote:<br>> Ok, I have clearly missed this part!!!<br>><br>> So, the points have to be ordered in a counter clockwise fashion???<br>> Why is that???<br>><br>> Cheers,
<br>> Anja<br>><br>> On 30/10/06, * Dean Inglis* <<a href="mailto:dean.inglis@sympatico.ca">dean.inglis@sympatico.ca</a><br>> <mailto:<a href="mailto:dean.inglis@sympatico.ca">dean.inglis@sympatico.ca</a>
>> wrote:<br>><br>> Hi Anja,<br>><br>> is your polydata always defined such<br>> that the points forming a closed loop are<br>> ordered counter-clockwise or equivalently,<br>> always clockwise and the vtkImageStencil set
<br>> accordingly?<br>><br>> Dean<br>><br>><br>><br>><br>><br>> --<br>> Cheers,<br>><br>> Anja<br>> ------------------------------------------------------------------------<br>
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<br>-- <br>Cheers,<br><br>Anja