John, Look at vtkStructuredGridVolumeRepresentation, It passes a "ExtentTranslator" to the view. The view uses the extent translator to build the KdTree. That's one of specifying the cuts. You can indeed provide a custom extent translator or if need be, that API can be extended to pass some other data-structure to extract the relevant information for ordered compositing.
For using opacity with polygonal data, simply go to the lookup table editor dialog and (in the advanced mode) you'll see a checkbox to "Enable Opacity Function". Check that and you can specify the opacity function. Utkarsh On Mon, Nov 19, 2012 at 10:49 AM, Biddiscombe, John A. <biddi...@cscs.ch>wrote: > Thanks Ken,**** > > ** ** > > My suspicions are confirmed. I had a poke around with the ordered > compositing code (vtkOrderedCompositeDistributor et al) and saw that the > BSP cuts from the D3 filter are set to match those from the PKDTree > internally. I notice that in the BSPcuts code it says**** > > // Description:**** > > // Initialize the cuts with arrays of information. This type of**** > > // information would be obtained from a graph partitioning software*** > * > > // package like Zoltan.**** > > ** ** > > Do you know if there exists such an example. I am infact partitioning the > data using Zoltan and have the exact bounds etc of the partitions, so I can > work out what to pass into the BSPcuts class and could potentially fool > the IceT composiining into using my partitions. Can you point me to any > crucial function that I must call. Is it sufficient to do a SetCuts on the > compositing code – which class do I need to take control of?).**** > > ** ** > > I shall create a custom representation to handle the depth sort. I’ve done > the same some time ago for the point sprite renderer so I’ll manage that > ok, but I’ll need to override the IceT compositing pass too as alluded to > above , so any pointers welcome. (Could I somehow subclass on of the > painters for the IceT pass and set the cuts to what I’ve got, then proceed > as usual?)**** > > ** ** > > Thanks**** > > ** ** > > JB**** > > ** ** > > *From:* Moreland, Kenneth [mailto:kmo...@sandia.gov] > *Sent:* 19 November 2012 16:13 > *To:* Biddiscombe, John A. > *Cc:* paraview-develop...@paraview.org; paraview@paraview.org > *Subject:* Re: [Paraview-developers] (Ordered) Compositing question.**** > > ** ** > > You are correct in that if you disable ordered composite it will disabled > the distribution and the composite ordering. The problem is that the > geometry distribution also creates a k-d tree structure that the > compositing uses to determine the visibility order. So it would not be > sufficient to simply have geometry that is in non-overlapping pieces. You > would also have to provide some meta-structure that could be used to > determine an appropriate ordering given a viewpoint. Even if you had that, > there is no mechanism to feed that to the compositor in the view. I can't > think of any way of doing that that would not be a huge hack.**** > > ** ** > > As far as I know, there is no support for the DepthSortPolyData filter. > You would probably have to create a custom representation to support that. > **** > > ** ** > > I believe the transparent lookup table for poly data is supported in 3.98, > but to be honest I have not yet tried it.**** > > ** ** > > -Ken**** > > ** ** > > Sent from my iPad so blame autocorrect.**** > > > On Nov 19, 2012, at 3:46 AM, "Biddiscombe, John A." <biddi...@cscs.ch> > wrote:**** > > I have geometry distributed into parallel pieces such that they are non > overlapping and therefore compositing should only need to use a back to > front sort last frame buffer operation with no redistribution of geometry. > **** > > **** > > I’m worried that when I turn on transparency, paraview will try to > redistribute my data, even though I have already partitioned it nicely for > this. I’d like to use ordered sort last compositing at the top level, and > use DepthSortPolyData on each node (no depth peeling for now) to ensure I > get a true image. What isn’t clear to me is if I “disable ordered > compositing” if this disables the transfer of geometry AND also disables > the ordered compositing necessary for correct transparent blending (I may > be confused here about the blend modes used or the term “ordered > compositing” as used in the docs).**** > > **** > > Is there written down anywhere a complete description of the pipelines > used by the various rendering modes so that I can be sure the pipeline is > doing what I want. I can create a custom representation which does what I > want, but it’ll take time and if the existing mechanism support it, I > shouldn’t need to.**** > > **** > > Also, I specifically want to use a transparent lookuptable, does the newer > paraview 3.98 have anything to support this. I thought I’d seen a thread > about this recently, but cannot find it now.**** > > **** > > In summary : For the rendering, I’d like Ordered sort-last compositing, no > geometry redistribution, Depth sort of polygons on each node. Transparent > lookup table.**** > > **** > > What settings should I use J**** > > **** > > Thanks**** > > **** > > JB**** > > **** > > -- **** > > John Biddiscombe, email:biddisco @.at.@ cscs.ch**** > > http://www.cscs.ch/**** > > CSCS, Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.07**** > > Via Trevano 131, 6900 Lugano, Switzerland | Fax: +41 (91) 610.82.82**** > > **** > > _______________________________________________ > Paraview-developers mailing list > paraview-develop...@paraview.org > http://public.kitware.com/mailman/listinfo/paraview-developers**** > > > _______________________________________________ > 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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