Utkarsh,<br><br>Thanks very much for your reply. I appreciate it.<br><br><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="im">> 1. I would like to know more about the algorithm that is used in Paraview to<br>
> do volume viz. I have used Paraview to viz a cartesian grid data set with<br>
> reaonable success. I can not seem to locate in the documentation much at<br>
> all about just which algorithm is being used. And how come there is a need<br>
> to stuff the data through tetrahedralize first?<br>
<br>
</div>What is your data type? If it's a vtkImageData then you shouldn't need<br>
to tetrahedralize. If it's vtkStructuredGrid then you'll need to<br>
tetrahedralize since ParaView currently only supports volume rendering<br>
for regular cartesian grids i.e image data and unstructured grids.<br></blockquote><div><br>My data is a 31x31x31 array of doubles in a 3d cartesian grid. The vtk file header plus a couple of numbers is:<br><br># vtk DataFile Version 2.0<br>
brillset_a6_n64_dx0p15625_gxx.dat<br>ASCII<br>DATASET STRUCTURED_POINTS<br>DIMENSIONS 31 31 31 <br>ORIGIN 0 0 0 <br>SPACING 0.412500 0.412500 0.412500 <br>POINT_DATA 29791 <br> SCALARS gxx float <br>LOOKUP_TABLE default <br>
1.00006867<br>1.00006955<br>...<br>...<br>...<br><br>so, it's structured. The min is .953... and the max is 1.030... so it covers a pretty modest range. I have viewed this data with Paraview and thought I had to stuff it through tetrahedralize first...was wondering how come?<br>
The volume viz of it shows most of the action is in the middle of the volume. Have played around with diverging and other maps. Have run isosurface on it with success.<br><br>I am just trying to understand what methods are being used in Paraview in order to better learn how to do better viz. <br>
<br> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<br>
For image data, ParaView uses fixed-point-ray-cast mapper (software)<br>
or a gpu-based raycaster. For details for the two algorithms used look<br>
at<br>
* <a href="http://www.vtk.org/doc/nightly/html/classvtkFixedPointVolumeRayCastMapper.html#_details" target="_blank">http://www.vtk.org/doc/nightly/html/classvtkFixedPointVolumeRayCastMapper.html#_details</a><br>
<br>
For unstructured grid, we have:<br>
<br>
* ZSweep - <a href="http://www.vtk.org/doc/nightly/html/classvtkUnstructuredGridVolumeZSweepMapper.html#_details" target="_blank">http://www.vtk.org/doc/nightly/html/classvtkUnstructuredGridVolumeZSweepMapper.html#_details</a><br>
* Projected Tetrahedra -<br>
<a href="http://www.vtk.org/doc/nightly/html/classvtkProjectedTetrahedraMapper.html#_details" target="_blank">http://www.vtk.org/doc/nightly/html/classvtkProjectedTetrahedraMapper.html#_details</a><br>
* Sofware Raycaster (Bunyk) -<br>
<a href="http://www.vtk.org/doc/nightly/html/classvtkUnstructuredGridVolumeRayCastMapper.html#_details" target="_blank">http://www.vtk.org/doc/nightly/html/classvtkUnstructuredGridVolumeRayCastMapper.html#_details</a><br>
* HAVS Mapper -<br>
<a href="http://www.vtk.org/doc/nightly/html/classvtkHAVSVolumeMapper.html#_details" target="_blank">http://www.vtk.org/doc/nightly/html/classvtkHAVSVolumeMapper.html#_details</a><br>
<div class="im"><br></div></blockquote><div><br>Thanks very much for the pointers. Will take a look.<br> <br></div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="im">
<br>
> 2. I have recently taken a look at the vtk examples for volume viz. They<br>
> are nice. However, I decided to take a look at modifying SimpleRayCast.py<br>
> to viz my 31^3 data set i doubles but seem to find that the routine which<br>
> does the heavy lifting does not take doubles. What do I need to do first to<br>
> make use of this example?<br>
<br>
</div>You may want to use something like vtkImageShiftScale<br>
(<a href="http://www.vtk.org/doc/nightly/html/classvtkImageShiftScale.html" target="_blank">http://www.vtk.org/doc/nightly/html/classvtkImageShiftScale.html</a>) to<br>
transform your data to the appropriate type.<br>
<font color="#888888"><br></font></blockquote><div><br>I guess not, as my data isn't an image.<br><br><br>Thanks again for taking the time to answer my questions.<br><br>Comer<br> </div></div><br>