<DIV>
<DIV>Hello,</DIV>
<DIV>I have a vtkStructuredPoints which contains some interesting values but also some "empty" values (=0) that are viewed in black, all around the interesting object which is composed by points from values 1 to 255. I would like to not see points with value zero, in order to "free" the object inside. I tried to play with a vtkLookupTable in order to assign a null alpha value to black points (=0) but it didn't work. The mapper seems to ignore my changes to its lookuptable. Here is an example. How can I filter black values without modifying my vtkStructuredPoints.</DIV>
<DIV> </DIV>
<DIV>package require vtk<BR>package require vtkinteraction<BR>package require vtktesting</DIV>
<DIV>vtkMath math</DIV>
<DIV># 20x10x10 points<BR>set numberOfInputPoints 2000</DIV>
<DIV>vtkUnsignedCharArray scalars<BR>for {set i 0} {$i < $numberOfInputPoints} {incr i 1} {<BR> scalars InsertNextTuple1 [math Random 0 255]<BR>}</DIV>
<DIV>vtkStructuredPoints cloud<BR> cloud SetDimensions 20 10 10<BR> cloud SetOrigin 0 0 0<BR> cloud SetSpacing 1 1 1<BR> [cloud GetPointData] SetScalars scalars</DIV>
<DIV>vtkDataSetMapper mapper<BR> mapper SetInput cloud<BR> mapper SetScalarRange 0 256</DIV>
<DIV>vtkActor actor<BR> actor SetMapper mapper</DIV>
<DIV>vtkRenderer ren<BR> ren AddActor actor<BR> ren SetBackground 0 0 0</DIV>
<DIV><BR>vtkRenderWindow renWin<BR>renWin AddRenderer ren</DIV>
<DIV>vtkRenderWindowInteractor iren<BR>iren SetRenderWindow renWin</DIV>
<DIV>renWin SetSize 500 500<BR>renWin Render</DIV>
<DIV>iren Start</DIV>
<DIV>wm withdraw .</DIV>
<DIV> </DIV>
<DIV>Later, I would like to create a slider that allows the user to filter viewed values from 0 to 255. How to do that ?</DIV>
<DIV>I attach a screenshot that shows my problem. I have a 3D object but I can't see it well. Black values are undesirable.</DIV>
<DIV> </DIV>
<DIV>Thanks.</DIV>
<DIV> </DIV>
<DIV>Aurélien</DIV></DIV><p>
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