[vtkusers] Mappers and vtkLookupTable

[Allen Sanderson]

Thanks David, we thought that was the case. 

Let me ask a somewhat parallel question. When rendering lines one typically sets a line width and sends the geometry downstream. The lines will be colored base on a variable but the line width is constant. At the same time when doing point glyphs we set the color and size based on a variable. If we wanted to vary the line width using a variable is our only choice to use a cylinder?

Cheers,

Allen


Allen Sanderson
SCI Institute
University of Utah
www.sci.utah.edu



> On Feb 16, 2016, at 12:20 PM, David Gobbi <david.gobbi at gmail.com> wrote:
> 
> Hi Allen,
> 
> You are correct, vtkLookupTable does not provide a way of doing this.
> 
> I'm not sure what work-arounds there are for geometry, but for images
> you can map the RGB and A separately, and then combine them into
> RGBA with vtkImageAppendComponents.
> 
>  - David
> 
> 
> On Tue, Feb 16, 2016 at 11:48 AM, Allen Sanderson <allen at sci.utah.edu <mailto:allen at sci.utah.edu>> wrote:
> Hello,
> 
> We are trying to render geometry using a lookup table for the RGB value using one scalar variable, but we want to use a secondary scalar variable for determining the opacity.  Something like the following:
> 
> RGB -> variable one
> A -> variable two
> 
> In looking through the VTK 6 documentation on mappers we have not found anything that leads us to believe this functionality is possible. But we have done an exhaustive search.
> 
> If it is possible we would greatly appreciate pointers. Thanks.
> 
> 
> 
> Cheers,
> 
> Allen
> 
> 
> Allen Sanderson
> SCI Institute
> University of Utah
> www.sci.utah.edu <http://www.sci.utah.edu/>
> _______________________________________________
> 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 VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ
> 
> Search the list archives at: http://markmail.org/search/?q=vtkusers
> 
> Follow this link to subscribe/unsubscribe:
> http://public.kitware.com/mailman/listinfo/vtkusers

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20160216/b8f95aea/attachment.html>