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How to walk through walls using the 4th dimension [video]

marctenbosch.com

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Re: How to walk through walls using the 4th dimension [video]

#21
post #8

Earlier quoted context omitted.

This game isn't real life! In the game there are four spatial dimensions, just because the game designer decided to have four.

Which is an awful lot like a 4th dimension. Arguably we are all 4th dimensional travellers, albeit somewhat constrained along one of the axes. Granted, you had me at “This game isn't real life!”

Oh, and the game also has a time dimension (which works normally I think, just one-way at one speed), so I guess that's 5 :)

Re: How to walk through walls using the 4th dimension [video]

#23

The game looks fascinating. I'm still trying to get my had around the analogies, but get the feeling that playing the game for real will bring a level of intuition to the experience. In the meanwhile, can anyone help me out? In the 2D->3D example, you have one shared axis (Z -- vertical), and an alternating pair for the second axis (X and Y -- horizontal). In effect, from the 2D character's point of view, 'jumping' i…

In the first case, the 1D vertical line is the same, but it's "seen" from a different angle. It looks the same because it's 1D and it doesn't happen to change because of the rotation.

For the second case, maybe it's the ground plane that's the same; it certainly has some of the initial texture in it, but it's been rotated and it's now seen from a different angle. But now we can tell the different because it varies along the dimensions it rotated around.

Or maybe I just can't visualize the rotation through the fourth dimension... I'm not sure.

Re: How to walk through walls using the 4th dimension [video]

#24

  Flatland: A Romance of Many Dimensions is an 1884 satirical novella
  by the English schoolmaster Edwin Abbott Abbott. Writing pseudonymously
  as "A Square", the book used the fictional two-dimensional world of
  Flatland to comment on the hierarchy of Victorian culture; but the
  novella's more enduring contribution is its examination of dimensions.
"A Square" feels sorry for poor, limited "A Line", but can't wrap his two-dimensional head around what "A Sphere" can do.

https://en.wikipedia.org/wiki/Flatland

Re: How to walk through walls using the 4th dimension [video]

#25

This is exactly what Guacamelee does: https://www.youtube.com/watch?v=FQDwqrqAvwk

Yep, except it is in 3d. I was hoping for some continuous movement, but it looks like it only switches between two worlds.

Maybe they will implement some more levels to make it look seamless. But there is simply too much work to design the world in 4d as a single piece of land holds a lot more information.

Re: How to walk through walls using the 4th dimension [video]

#26

I was really hoping for a continuous (rather than discrete) fourth dimension. The concept is cool and looks to be well executed, but it's not very different from other alternate reality implementations such as the Dark World in Legend of Zelda.

That would be really cool. The mathematics involved don't seem too difficult; you have to add another axis to your vectors, points, and transform matrices, and you can place and orient your models in 4D space, set up lights and a camera in 4D space, and project the camera's view into 3D space first then onto the 2D display. I think the hard part is creating the models and writing the rendering engine. Creating 4D mod…

What would the 4th dimension coordinate of your models even represent, though? I'm having trouble wrapping my head around it.

Re: How to walk through walls using the 4th dimension [video]

#27
post #16

This is a very interesting way of explaining the 4th dimension by relating it to the difference between the 2nd and 3rd dimensions. However, I think what would really solidify my understanding is to see the 4D level editor. I'm not sure how truly 4D this world is, but it appears to let you switch between a fixed set of different 4 dimensional positions, each of which has a different 3D representation. Just as a plane…

That's not quite what a 4th dimension is like. In your example, the faces are completely separate from one another. But really they would be connected, in a continuous line. You'd be able to push something a little bit along the dimension, or run a long distance. You could rotate an object in 4D so that parts of it ware poking a little bit into each dimension at the same time.

Re: How to walk through walls using the 4th dimension [video]

#28
post #26

Earlier quoted context omitted.

That would be really cool. The mathematics involved don't seem too difficult; you have to add another axis to your vectors, points, and transform matrices, and you can place and orient your models in 4D space, set up lights and a camera in 4D space, and project the camera's view into 3D space first then onto the 2D display. I think the hard part is creating the models and writing the rendering engine. Creating 4D mod…

What would the 4th dimension coordinate of your models even represent, though? I'm having trouble wrapping my head around it.

Mathematically, they're identical to any other dimension. You can move a little bit into a fourth dimension just like moving a little bit left-to-right. Or you can rotate things around the fourth axis just like turning something clockwise. In the case of this game, he only shows a 2D projection of a 3D cross-section of a 4D world, so that might be adding to the confusion. What you see in the video is only 3D "slices" of a 4D object rotating.

Re: How to walk through walls using the 4th dimension [video]

#29

I was really hoping for a continuous (rather than discrete) fourth dimension. The concept is cool and looks to be well executed, but it's not very different from other alternate reality implementations such as the Dark World in Legend of Zelda.

That would be really cool. The mathematics involved don't seem too difficult; you have to add another axis to your vectors, points, and transform matrices, and you can place and orient your models in 4D space, set up lights and a camera in 4D space, and project the camera's view into 3D space first then onto the 2D display. I think the hard part is creating the models and writing the rendering engine. Creating 4D mod…

You could probably make something like Minecraft but out of hypercubes and besides turning in three dimensions you can also reorient your three dimensional subspace in the four dimensional world. As you mentioned, the interesting question is how you model objects - are our usual three dimensional things thin sheets in the fourth dimensions or do they have some interesting structure.

Re: How to walk through walls using the 4th dimension [video]

#30

I was really hoping for a continuous (rather than discrete) fourth dimension. The concept is cool and looks to be well executed, but it's not very different from other alternate reality implementations such as the Dark World in Legend of Zelda.

That would be really cool. The mathematics involved don't seem too difficult; you have to add another axis to your vectors, points, and transform matrices, and you can place and orient your models in 4D space, set up lights and a camera in 4D space, and project the camera's view into 3D space first then onto the 2D display. I think the hard part is creating the models and writing the rendering engine. Creating 4D mod…

This is something I've been working on as a side-project on and off for a while. It's complicated by the fact that every existing engine is built around the assumption that you only want to use 3 dimensions, not four, and not arbitrarily many, so I've been pretty much writing everything from scratch (and very limited GPU acceleration, as you said, because GPUs also assume 2 or 3D). So far, I'm punting on model building by just auto-generating 4D mazes with hypercubical cells, because maze-generation algorithms work in arbitrary dimensions.

For simplicity, my rendering engine is a dead-simple raytracer which doesn't even bother with reflections- just cast rays and record the first surface they run into. Handling rotations and projections is really easy, but there are two problems I have found:

1. It's just really frickin' slow. Raytracing just ain't fast enough, though I may be able to find some additional optimizations to make it better.

2. In terms of gameplay, navigating the space is really, really hard. It is so easy to get completely lost regarding which direction you're facing and what hyperplane you're on when you can make arbitrary rotations in all four dimensions. It might be something I could get used to, but so far I feel like it's practically necessary to have some mechanism that will snap you back into alignment with some set of gridlines.

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