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<body class='hmmessage'><FONT size=3>Hi , vtkusers ,</FONT><BR>
<FONT size=3></FONT> <BR>
<FONT size=3> My friends ask me how to compute the area or volume of vtk rendering object . My thought is :</FONT><BR>
<FONT size=3></FONT> <BR>
<FONT size=3> 1 . we know , if the region , which would be computed , is regular , the computation will be </FONT><BR>
<FONT size=3>easy . </FONT><FONT size=3>in fact , however , what we have to compute are always arbitrary polygons . there are several </FONT><BR>
<FONT size=3>methods : </FONT><FONT size=3>we can divide it into several triangles , computing each triangle's area and then sum </FONT><BR>
<FONT size=3>them up . but there is a precondition : the polygon have few points . the more points , the more </FONT><BR>
<FONT size=3>difficult it is . </FONT><BR>
<FONT size=3> Is there any filters that can compute the <FONT color=#0000ff><STRONG>arbitrary polygon's area </STRONG></FONT>? I test it in vtkMath , but </FONT><BR>
<FONT size=3>it </FONT><FONT size=3>just performs common math operations . </FONT><BR>
<FONT size=3> or , if there is not such a filter , I think it would be better to writer such a class , because </FONT><BR>
<FONT size=3>it </FONT><FONT size=3>will be used widely , like geology and so on .</FONT><BR>
<FONT size=3></FONT> <BR>
<FONT size=3> 2 . if we reconstruct a arbitrary 3D object , maybe we want to get its volume . I have been </FONT><BR>
<FONT size=3>thinking we can compute it by voxels ,because the voxel is regular , then we can compute it . but I </FONT><BR>
<FONT size=3>could not get the number of voxels in 3D object . I can only get the number of cells , but it would </FONT><BR>
<FONT size=3>not help me . </FONT><BR>
<FONT size=3></FONT> <BR>
<FONT size=3> so , if we want to compute <FONT color=#0000ff><STRONG>volume</STRONG></FONT> , what filters we can use ? </FONT><BR>
<BR>
<FONT size=3> thank you with great regards !</FONT><BR>
<FONT size=3> </FONT><BR>
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