Any tips for raytracing a black hole?

[acdemiralp]

Dear Dr. Mueller,

Thank you for the Catalogue of Spacetimes and this library which contains years worth of code. You have effectively introduced me to numerical relativity in a matter of months, which I feel would take years with a literature-only approach.

I am a doctoral student working on scientific visualization, particularly with postmortem brain data, yet the topic of relativity has boggled me long enough that I had to learn it on the side. My current goal is to write a physically-correct raytracer, which follows the metrics defined in this library, yielding simulated results complementing the recent empirical M87* images.

Have you ever done something similar? Do you have any ideas or tips on how to proceed?

[acdemiralp]

My current plan is:

• Generate rays using the observer and the image plane. Rays are defined on the image plane as unit vectors and are traced backwards in time to their origin.
• Obtain the given metric's Christoffel symbols and their derivative for each ray (if applicable, use Cartesian coordinates).
• Use geodesic motion to integrate through the ODE for each ray. Iteration leads to the origin of the given ray.

Does this look correct to you?

[tauzero7]

Dear Ali Can Demiralp,

 

during my PhD I've developed a ray tracing software called GeoViS which is based on my motion4d library https://www.visus.uni-stuttgart.de/publikationen/geovis/

Unfortunately, the links to the images on the old web page are broken.

 

You find some videos on https://www.youtube.com/user/relavis which I've rendered with GeoViS.

 

Your plan corresponds to the standard ray tracing concept. So good luck and let me know if you have rendered some nice images..

 

Cheers, Thomas

 

Gesendet: Freitag, 03. Mai 2019 um 14:03 Uhr Von: "Ali Can Demiralp" notifications@github.com An: tauzero7/Motion4D Motion4D@noreply.github.com Cc: Subscribed subscribed@noreply.github.com Betreff: [tauzero7/Motion4D] Any tips for raytracing a black hole? (#2)

Dear Dr. Mueller,

Thank you for the Catalogue of Spacetimes and this library which contains years worth of code. You have effectively introduced me to numerical relativity in a matter of months, which I feel would take years with a literature-only approach.

I am a doctoral student working on scientific visualization, particularly with postmortem brain data, yet the topic of relativity has boggled me long enough that I had to learn it on the side. My current goal is to write a physically-correct raytracer, which follows the metrics defined in this library, yielding simulated results complementing the recent empirical M87* images.

Have you ever done something similar? Do you have any ideas or tips on how to proceed?

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[acdemiralp]

Dear Dr. Mueller,

Thank you very much for the insight. The Morris-Thorne wormhole videos are brain freezing. I will look further into them after regular Schwarzschild, Kerr, Reissner-Nordstroem and Kerr-Newman black holes.

I will try to do this using several hundred computers to run the simulation in real-time through MPI so that one can move the observer dynamically, even in a virtual reality headset, which requires an update rate of 11 milliseconds / frame. I will update you as soon as I get first results.

Ali