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Re: [Manta] Re: Manta: Direct isosurfacing using octrees


Chronological Thread 
  • From: Aaron Knoll <knolla@cs.utah.edu>
  • To: uccaspa@ucl.ac.uk
  • Cc: MANTA <manta@sci.utah.edu>
  • Subject: Re: [Manta] Re: Manta: Direct isosurfacing using octrees
  • Date: Mon, 22 Oct 2007 08:37:00 -0700
Hi Shree --

One problem with the octree data is that it currently only supports single-byte scalar data, not 32-bit float.

To fix it, one would have to do a fair amount of modification in the code. It shouldn't be very hard modification, and the octree volume should work (in fact, it should work relatively better, as the size of pointers is smaller relative to the size of data).

However, in the meantime, can you downsample your data to unsigned char instead? You can use a tool like "unu" from the nrrd package to do this:

http://teem.sourceforge.net/nrrd/demo.html

-Aaron

On Oct 22, 2007, at 8:31 AM, uccaspa@ucl.ac.uk wrote:

Ok, I found the problem and it was just a stupid mistake on my part.
I was passing the complete path of the .otd file to Manta instead of just the filebase (i.e. the path minus the .otd file extension). Hence, Manta was unable to read my generated octree data file and created an empty data structure resulting in a segv when this was raytraced.

DOH! Well, at least this has familiarised me with the code :)

Manta now appears to render the octree data as the debugger now shows the data to be populated. However, although the FPS are displayed nothing is actually visible in the render window? Do you have any idea why?

FYI, I've included a screenshot and links to the data files I'm using here:

http://ccs.chem.ucl.ac.uk/~shree/

On Oct 21 2007, Aaron Knoll wrote:

> OctNode& node = octdata->get_node(depth, node_index);
That's the basic point-location lookup routine for a node. Usually when this fails, it's because the data isn't built correctly.




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