Ken is right. 0 is full opacity and 1 is full transparency.
Moreland, Kenneth wrote:
The correct expression for radiative transform defines light attenuation per unit length. The Scale value allows you to set what that unit length is. The larger the unit length, the further light has to travel to attenuate the same amount. Your description of the behavior seems backward. If you set the unit distance to 0, you should see full opacity. It means that when light travels 0 distance it's attenuated a finite amount. Thus, any finite distance should attenuate all light. The larger you make the unit distance, the more transparent the rendering should become. This is the behavior I get with disk_out_ref. Are you sure you didn't get it backwards? -Ken **** Kenneth Moreland *** Sandia National Laboratories*********** *** *** *** email: [email protected]** *** ** phone: (505) 844-8919 *** web: http://www.cs.unm.edu/~kmorel On 8/2/11 11:21 AM, "Jeff Mauldin" <[email protected]> wrote:I am working with volume rendering on a particular data set. I am doing projected tetra volume mapping. When I bring up the Color Scale Editor dialog (which I have used extensively), there is an entry called "Scale" that I haven't been able to find documentation to. In playing with the python tracing, I see that it alters a value called ScalarOpacityUnitDistance. The effect appears to be that setting this parameter to zero causes the rendering to be completely invisible (alpha zero everywhere, presumably) and setting it to 1 causes the rendering to be completely opaque. I'm guessing it's some kind of multiplier to the opacity value in color transfer function, and possibly some kind of multiplier applying to how much each volume ray segment contributes to the overall opacity of a pixel. What exactly is this scale value doing (so I can understand what I'm looking at)? _______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the ParaView Wiki at: http://paraview.org/Wiki/ParaView Follow this link to subscribe/unsubscribe: http://www.paraview.org/mailman/listinfo/paraview
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