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murkle commented on A simple way to generate random points on a sphere   johndcook.com/blog/2025/0... · Posted by u/piinbinary
egorfine · 17 days ago
Please forgive me my naivete, but won't generating two random polar coordinates do? I'm bad at math, so I might as well be very very wrong here, but I'd like to know.

Edit: see @srean's excellent explanation why that won't do.

murkle · 14 days ago
Yes, that does work basically. See https://news.ycombinator.com/item?id=45001593
murkle commented on A simple way to generate random points on a sphere   johndcook.com/blog/2025/0... · Posted by u/piinbinary
danwills · 17 days ago
I think it can be done that way yeah but in order to yield a uniform-density of points on the surface of the sphere there's some pre-correction (maybe a sqrt or something? I can't remember) that's needed before feeding the 'uv' values to the trig functions to make 3D positions. Otherwise points will 'bunch up' and be more dense at the poles I think.
murkle commented on A simple way to generate random points on a sphere   johndcook.com/blog/2025/0... · Posted by u/piinbinary
torrance · 14 days ago
The simplest way to do this is described here: https://mathworld.wolfram.com/SpherePointPicking.html

Essentially:

1. Generate uniformly random values u,v between 0 and 1.

2. Then find their spherical coordinates as:

theta = 2 pi u; phi = acos(2 v -1)

Honestly I’m unsure why you’d choose a method any more complicated.

murkle · 14 days ago
murkle commented on Generating (almost) equally-spaced points along a parabola   arjuns07.github.io/posts/... · Posted by u/sharma-arjun
murkle · 2 months ago
Works well for flat parabolas. For "tall" ones you can get a big jump just after the peak https://www.geogebra.org/m/eft5vqbd
murkle commented on A new pyramid-like shape always lands the same side up   quantamagazine.org/a-new-... · Posted by u/robinhouston
XCSme · 2 months ago
Does it work when 3rd printed? How sensitive is it to infill options or infill density variations?
murkle · 2 months ago
You need 100% infill to ensure it's working for the right reason.

I've got one mostly working with quite a lot of sanding

murkle commented on 0.9999 ≊ 1   lcamtuf.substack.com/p/09... · Posted by u/zoidb
fouronnes3 · 3 months ago
To me the most obvious proof is that therere are no numbers in between 0.999... and 1. Therefore it must be the same number.
murkle · 3 months ago
Exactly, add them up and divide by 2. What's the answer?
murkle commented on Putting Rigid Bodies to Rest [pdf]   cs.cmu.edu/~kmcrane/Proje... · Posted by u/murkle
murkle · 3 months ago
.STl files are available to download and print here:

https://www.cs.cmu.edu/~kmcrane/Projects/RestingBodies/suppl...

u/murkle

KarmaCake day785June 29, 2014View Original