Miguelaragon’s Blog


A fly through the Universe
March 5, 2009, 10:59 pm
Filed under: visualization | Tags: , , ,

This post describes the main steps in the making of a SDSS fly-though I have been developing since some time ago. I started with povray but moved to Blender due to its flexibility,  especially  with its python api.

Since its first light the SDSS has been continuously taking both images and spectra across the northern sky. The last data release (DR7) contains almost one million galaxies with spectra and many more galaxy images. From the +- million galaxies with measured redshift only a very small fraction has high quality images. This is mainly due to the intrinsic resolution of the telescope and the atmospheric conditions at the time of observation. In order to produce images with the desired quality each galaxy in the spectroscopic sample was matched with a high-res image from a template of galaxies. The matching was done by choosing the closest galaxy in color — concentration-index space. Elliptical galaxies were displayed as quad sprites with a dense bulge and a diffuse 3D halo.

Galaxy template

Galaxy template

Loading galaxies into Blender
Once all galaxies have been assigned an image from the template the next step is to load the galaxy’s position, size, inclination and image into Blender. The python interface provided by Blender makes this very easy.

Galaxies were binned by their respective templates. The all galaxies were loaded into a single object in Blender. So there are 300 objects each holding several thousand quads for each galaxy. This saves memory since there is no need to store all the possible properties for each galaxy.

Loading galaxies into Blender

Loading galaxies into Blender

In progress…

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3 Comments so far
Leave a comment

Hi!
I saw your fly through on Vimeo and was stunned. It is fantastic.
On Vimeo you mention that the original is in High resolution and stereoscopic. I am putting together a Hi-Def Stereoscopic projection system (using polarizers)and would love to view the fly-thruogh on it.
How can I do that?
Regards, Gary Welch

Comment by Gary Welch

miguel – this is astonishing in its depth – exactly the kind of visualisation tools we need to be able to grasp and explore some of the potentials of new geometry arising out of Misha Gromov’s work and some of the Bayesian paradigms in a ‘human’ way rather than twisting our heads around pencil and paper algorithm/mathematical grammar….I think in this way new discoveries and observations will become apparent and, at least ‘theoretical verifiable’ within the paradigms of the models themselves – at the very least, this is a wonderful playground you have constructed! love to keep in contact, sincerely, jez

Comment by jezhoughton

Hi jez, I had to google Misha Gromov in order to “understand” what you were talking about. Very dense stuff. I agree that a good visualization can lead to new discoveries. BTW I am working now on an improved version of the flythrough that will include Large Scale Structures in addition to the galaxies.

Comment by Miguel Angel




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