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spherical-volume-rendering / svr-algorithm

A spherical volume rendering algorithm that performs ray casting through a spherical voxel grid.
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AMR rendering issues #204

Open matthewturk opened 4 years ago

matthewturk commented 4 years ago

I'm running the system with an AMR dataset, and I'm getting some results that confuse me somewhat. I have a suspicion why they are doing what they are doing, but I cannot yet verify this.

To set the stage, I've loaded up a "fake" AMR dataset using yt.testing.fake_amr_ds(geometry = "spherical") and I'm rendering the field "ones".

With a random normal, [0.18617054, 0.15260178, 0.83324573], I get an image that looks like the attached. The min/max are 0 and 3.971; this is just under what I'd expect the max to be (4.0, for through-the-center).

hi_random

The AMR grids are well-defined, and the total enclosed volume is correct. It looks to me, however, like it's not fully traversing some of the grids. I am not sure if this is because they need to be entered by rays twice (which is definitely possible), but I am working on figuring that out. So I will get back to you. I just wanted to give an update.

I'm starting to suspect that I'll need to use the walkSphericalVolume function to compute the order of traversal for the grids.

cgyurgyik commented 4 years ago

Thanks for the update. I'll follow this; please let me know if you have any questions in regards to walkSphericalVolume.

ak-2485 commented 4 years ago

Hi Matt. To be clear, you are expecting a completely symmetric image? What are num_polar_sections and num_azimuthal_sections here? And, what are the min and max bounds used?

matthewturk commented 4 years ago

Hi Ariel,

This is feeding in lots of little grids, where num_polar and num_azimuthal may differ. I'm working on a tiny replicable example, which I should be able to share tomorrow.

On Thu, Aug 6, 2020 at 8:35 PM Ariel Kellison notifications@github.com wrote:

Hi Matt. To be clear, you are expecting a completely symmetric image? What are num_polar_sections and num_azimuthal_sections here? And, what are the min and max bounds used?

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