I've parallelized the volume renderer in hg. It will decompose both grids (but not bricks! -- the distinction is important for large root grid tiles) across processors, as well as cutting the image plane into bits. I was getting artifacts, but now I am no longer getting them. The scaling hasn't been great so far, but it's been pretty good, and it should certainly assist with memory issues.
To get it going, I added a new object, VolumeRendering, that hangs off the hierarchy (like other objects.) You shouldn't need to do anything special besides "--parallel" to run it in parallel. The old direct_ray_cast probably doesn't work, as I had to change the arguments to the VectorPlane object to allow for non-square volume renderings.
Here's an example script:
There's some calculation in here of the L vector and whatnot. Additionally, this uses the new image saving routines Sam put in yesterday (awesome work, Sam!).
Let me know what you think! I'm going to try testing this out to see how well it scales for very large tiles as well as very large data.
I've parallelized the volume renderer in hg.
That's great! I haven't actually used it yet, but it looks super useful. I wonder, can one use a different field to volume render besides Density? _______________________________________________________ email@example.com o__ Stephen Skory http://physics.ucsd.edu/%7Esskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________
That's great! I haven't actually used it yet, but it looks super useful. I wonder, can one use a different field to volume render besides Density?
Definitely. As of right now,
it's an argument. Hopefully soon we'll be able to use one field for RGB and another for Alpha. I dug back into the source code this weekend to do the aspect ratio and decomposition, so I think I know how to stick in the second field without any real overhead, and it's just going to be a matter of getting a transfer function that'll help us test it! Jeff & John, I know you had both expressed a lot of interest in this -- do either of you have a set up for a rho&T dependent transfer function?
us test it! Jeff & John, I know you had both expressed a lot of interest in this -- do either of you have a set up for a rho&T dependent transfer function?
I don't at the moment, but I will be working on this later tonight or tomorrow. It's next on my list after my current Orion debugging completes. I really would like to show a multi-variate TF render on my poster for the Austin PopIII meeting in two weeks. I'll send a message to the list when I have something.