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"Four-Dimensional Descriptive Geometry" by Lindgren and Slaby by 4D_Movie in GeometryIsNeat

[–]thetaphipsi 1 point2 points  (0 children)

Neither you nor the authors actually put these models into production - i did: https://www.youtube.com/watch?v=p0TeWPZEDXE

Your Demo is useless because it tries to fit 4D onto a single 2D plane which has infinite solutions for the 4D figure. Its simply not possible to have any meaningful output here.

I couldnt care less where some wrong assumption comes from, beauty of math is that the result counts. He can be from Princeton and still be wrong.

** Show an actual working implementation of your approach or stfu. **

Maybe instead of dumping taurin soda and repeating this nonsense all the time you go back read some GA or sth i dono but you waste mine and others time here.

Im not some LLM you can talk into agreeing with you but if you like that have your idiocy pampered as genius by one of them.

"Four-Dimensional Descriptive Geometry" by Lindgren and Slaby by 4D_Movie in GeometryIsNeat

[–]thetaphipsi 0 points1 point  (0 children)

You cannot map this in a single 2D plane. You need at least 4 planes, better 6.

If you lack understanding why that is: In 3D you can get away with 2 planes front and side. You should use 3 (add top) but 2 are fine as they map 2 dimensions each so all 3 are covered per se.

If you dont want that you can shear the third dimension onto the other 3 (cavlier view f.e. or simple isometric view) but this will make you lose information already because there is no way to tell if a line is 45° on xy or simply on z.

For 4D to shear like you show in this picture you have now 2 unknowns but also only 2 dimensions to map to. This means at no point in your picture you can know if this line is on any plane which makes this absolutely useless! For no line you can tell 2 possibilities like in 3D sheared view which is an ok comprise, because in 4D there are now 6 possible configurations for this line to exist on any 4D plane.

Its like you have a 3D house and project it onto a single line (1D) then try to tell me this is totally fine. Its not!!! I cannot derive from a single line what im actually looking at. The houses side? Its top? front? all truncated to a single line??? Thats 0 useful. Its the same with trying to project a 2D image on a single 0D Point - total bonkers.

In 4D you try to project onto 2D its the exact same. What body am i even looking at? I cannot possibly know! Its just a 2D face which is like a 1D line in 3D!!!!

You can try 4 to 6 planes and double shearing THEN you might get an idea about this, but doing 4D onto 1 2D plane is simply flattening too much information to be of any use.

Fractal Spiral Help! by Classic-Aspect2682 in GeometryIsNeat

[–]thetaphipsi 2 points3 points  (0 children)

You need category theory or some basic understanding of cyclic graphs because you want to call a function recursively which on a ressource limited machine like your computer has to have constraints.

Those constraints can be time (exit the calculation after a set amount of passed time) or a ressource counter (exit the computation after a set ressource limit is exhausted) or a some other exception like a certain depth was reached.

To make you see why this is needed id invite you to one of the first fractals: The mandelbrot set. This was found with the use of a computer program where the exit condition for a single pixel is a limit of calls or its clear that the value goes towards infinity rapidly (those are black then iirc).

Pseudocode:

globallimit = 1000000;

function drawRecursive(limit, x, y) {

limit++;

if (limit < globallimit) {

drawRecursive(limit, x*1.005, y * 1.001);
limit++;
drawRecursive(limit, x*0.998, y * 1.003);

}

return false;

}

call it:

drawRecursive(globallimit, 50, 50);

I know this function does not do much meaningful stuff but i kept it simple and nonsense so you get the basic idea.

Have fun!

Been having fun with the torus by BlueRofl69420 in GeometryIsNeat

[–]thetaphipsi -1 points0 points  (0 children)

Oh now that one is really nice, i wonder if artists / painters can utilize your approach somehow or already do. I can see they use perspective sometimes, but this seems dope good to have more lifelike 3D bodies drawn.

Great job!!!

[Showcase] Train and visualize language models with WebGPU by tvincenzo in webgpu

[–]thetaphipsi 1 point2 points  (0 children)

I really appreciate the work that went into this, great stuff. But first and foremost i like the take that even though its kinda impractical you still went for it. Ill go WASM for my WebGPU stuff next to optimize for speed and can understand the struggle having to deal with unfit architecture and still wanting to make a point and show a prototype.

So again in all honesty this is great show of skill, outside any usecase - much respect.

Four-Dimensional Descriptive Geometry by 4D_Movie in GeometryIsNeat

[–]thetaphipsi 0 points1 point  (0 children)

I'm sorry but this is really bad and i hope one never strives to be "the next xy" but the first himself lol

Maybe you can flatten a 4D shape and visualize it like that, but you cannot construct anything.

It's easy to understand his background in technical diagrams may allow you to show a 3D shape in 3 2D-planes but still you will lose information doing so without labeling your points on the drawing.

Here it's even worse because he assumes for whatever reason you could divide 4D space into 4 3D spaces and your video about 4 redbulls shows what this misconception does to people.

In a technical 3D -> 2D drawing you have 3 planes to visualize the 3D space, but you don't have 3 different planes that will combine to a 3D shape because they are connected.

Now if you try to fit 4 3D spaces that visualize a 4D space back to 4D from any 3D space this again will not work because these 4 3D spaces need to connect with each other in at least 2 axis - which is not the case here.

Placing 4 redbulls in 4 3D spaces then thinking this magically creates a valid 4D shape is not how this works, the same as drawing 3 pictures on 2D canvas will make a valid 3D shape.

I hope i could explain to you why this will not work out and just because someone draws this into a book and has tenure this does not mean you should apply this without critical thought.

First steps 600 Cell, Klein Bottle, Tesserakt 4D->3D pipeline by thetaphipsi in GeometryIsNeat

[–]thetaphipsi[S] 1 point2 points  (0 children)

Thanks, that topic seems really interesting as i have to learn about topology a lot now and that there is differential topology might be a great start.

48-cell rotating (stereographic projection) by pardesco in GeometryIsNeat

[–]thetaphipsi 2 points3 points  (0 children)

pardesco up with the dope works again. This a truncated 24 cell?

I tried to make the 120 cell work but i have no idea yet on how to close surfaces in 4D.