How I made a 3D Level in a 2D Game

what you're watching right now is a custom level entirely within the 2D mobile game Geometry Dash now you might think this is a weird mod or something but no this is just the most complex Geometry Dash level ever made everything in this level is made entirely out of 2D Geometry Dash objects and they all become 3D through their own little Illusions and magic tricks like look at this tunnel in the background for example this looks completely impossible to make out of just gomad Dash objects but when you understand how it works it's actually quite simple see if you've ever looked into a spinning spiral like this one you'll notice that it kind of looks like everything is getting smaller and moving towards the center which is also what happens when you move away from something in 3D space everything gets smaller as it gets further away from you now this spiral doesn't look 3D yet but that's just because the points in this spiral are moving at a constant speed while in 3D things going away move slower and slower if we change the curvature of the Spiral arms we can actually make them move in the same way things do in 3D space and if we now make a second spiral flip it and make it rotate the other way and put the two spirals on top of each other we get a quite convincing 3D tunnel illusion this is pretty cool but let's take it a few steps further we can make the spiral arm solid by creating them out of slope and square objects but this of course hides the second spiral and we can't really make it transparent arent because that'll ruin the effect except if we use colors that max out one or more of the RGB channels of the color and then set them to blending the overlaps between the objects will be hidden and if we combine this with some clever layering and some shading we get a pretty cool looking realistic threedimensional tunnel made entirely out of spinning Geometry Dash objects wow that's pretty neat I said two years ago and it could have ended there should have ended there but no because I'm a level Creator and nothing I make has any value unless it ends up as a 60c level on the job to that serers now I could just use this tunnel thing in the background of a normal level but wouldn't it be pretty cool if I just kept making these kinds of 3D illusions until I get a whole level that's entirely 3D surely it can't be that hard of course to convince your brain that you're looking at something truly three-dimensional everything in the level has to be a convincing 3D illusion like even the player look at the player in this part it's actually completely fake the real player is actually squished strangely up at the top here in an entirely different game mode see we can't really use the buil-in Geometry Dash game modes for this level because well they're in the wrong number of Dimensions so instead we have to hide the Real Player and construct a fake player from the ground up programmed using triggers and visualized using illus iions to behave exactly like the player usually does in the game except one dimension higher this fake player is made up of two components The Head and the trail the head is actually pretty simple it just goes through seven frames of rotation every time the wave changes Direction which it does every time this touch trigger detects that the player is pressing a button and each one of those rotation frames also has 10 different perspective variations which just means I had to handmake 70 different precise pyramid shapes out of slopes and squares this was not the part that started my descent into madness this is the trail it's made out of hundreds of layers of ellipses which all mimic the movement of the head but with more and more delay making the movements appear to Cascade through them now this doesn't sound too bad but to make it look three-dimensional we obviously have to make the ellipses and their movement bigger as they get closer to you but to make the way they get bigger fit in with all the other 3D illusions in this part this has to be done in a really mathematically specific way so to figure that out I recreated the camera angle in the 3D modeling software so that I could render out 14 different realizations of ellipses which I can then overlap on top of each other and measure before putting all the values into an exponential regression model so that it could get a continuous function for the amplification of the movement at the position of each ellipse that's the easy part the hard part is to actually make these ellipses move with the correct delay at all see the normal way to do this is with a spawn trigger but its delay is actually based on the frame rate of the game which makes it way too imprecise to make a smooth Trail luckily we have the follow player white trigger whose delay is not based on frame rate and it was almost perfect but for some ungodly reason Rob up decided to arbitrarily hard limit this delay to 0. 01 seconds which is still too imprecise so instead I had to invent an entirely new technique where the ellipses are grouped into 0. 01 second interval segments and each group has two copies where one copy slopes up and one copy slopes down at very specific inclinations so that I could switch between them based on the slope of the curve at that group's position which made it barely possible to make a smooth looking Trail at the cost of taking literally a month to figure out and build which is already a frankly unreasonable amount of time to spend on a geometry dash level let alone a single element of it and is all because of these stupid arbitrary limitations but hey you did it me I mean at this point you might as well send R up a video of the level just to say fuck your stupid arbitrary dumb stupid limitations but don't actually say that of course that would be mean and I guess it's not really his fault you were compelled by some mysterious Force to attempt to make a 3D version of his 2D mobile game inside itself he's also spent the last 5 years working on this gigantic update to the game one that will change everything so fundamentally that it'll basically just make it a different game entirely which really puts a hard deadline on this whole level you're making since if you take too long suddenly the game you're making in it will just stop existing and this update seems to be just a few months away so actually you probably won't be able to finish level in time anyways I mean it's been almost 2 months and all you have is a sperm cell on an LSD trip it's sad but sometimes sometimes you just have to let things go and wait wait hold on he he actually [Music] replied man your 11-year-old self sure would be extremely excited right now he seems kind of impressed as well I guess seeing stuff like this might be one of the things that motivates him to keep developing this singular update for 5 years man imagine spending multiple years on a single project why would you put yourself through that anyways it doesn't even really matter cuz again you're definitely not continuing this project there's no way you'll even get close to finishing it before the update and even if you did it would just be an enormous waste of take a look at these 3D mountains to make them I first designed them in the 3D modeling software and then I wrote a script that takes each triangle in the mountain mesh and finds the intersection between the triangle and a vertical plane which gives us a line we can attach a geometry dash object too if we run this script for every triangle in the mesh adding one object where ever there's an overlap we can now build any 2D slice of these fountains out of just the Arad Dash objects if we now make 300 of these 2D slices on top of each other and scale the slices in the back down and the ones in the front up we suddenly have a projection of this 3D model made entirely out of moving 2D objects now let's add the player to this part faking the physics of this game mode with just triggers is actually surprisingly complicated so the first thing I did was that I made a programming language that lets me write code that turns into Geometry Dash triggers which means I could write all the complicated physics in my abstracted language and have my compiler compile it into actual geometer Dash triggers in the level to make the cube look three-dimensional I split it into six layers where the layers in the back are a tiny bit smaller and a tiny bit slower than the layers in the front making it look like the player shifts in perspective as it jumps up and down now our player is currently jumping in midair which is a sign that it might be time to add some platforms and obstacles and it's at this point things start to get kind of crazy because to anyone who's ever made something in the geometer Dash editor these obstacles look just completely impossible on several levels like these cubes are scaling and warping as they move closer to you but there is no scale trigger in Geometry Dash at least not until the giant update DRT up is making which is still just a few months away somehow now in the preview I released for this level I did sort of imply that these cubes were made by using thousands of rotat move triggers to sort of Puppeteer a bunch of objects around and this led to some people trying and failing to recreate this effect effect themselves what they didn't realize was that it actually employed this clever tactic called lying look most of these triggers are spawn triggered with no group they do nothing the technique I actually use is one that I think is much more fascinating and unique and is actually pretty similar to how real computers render 3D objects see in computer Graphics everything in the 3D world is made out of triangles but unfortunately it turns out to be impossible to make an arbitrary triangle out of Geometry Dash objects since the thinnest angle we can create with them is this 26.

6 de slope no matter how we arrange any of these thousands of types of objects you cannot make a shape with a smaller clean angle than 26. 6 de and an arbitrary triangle could of course have as small angles as it pleases we could try and make a thin angle with some lines or by using a fractal pattern but as you'll see in a bit it's also really important that this uses the absolute minimum amount of objects possible so instead of making a triangle let's make a cube the this might seem even more impossible at first but the added complexity actually turns out to make a cube possible to create even if a triangle is not see if you think about it no matter how you move or spin it around you can only ever see three sides of a cube at once and if we look at these three faces on a 2D image there will almost always be at least one face where all four of its angles are above 26. 6 de let's call this the front face since it's usually the side of the cube that's pointing towards you so since the front face only has legal angles we can pretty easily construct it out of Geometry Dash objects by putting one slope on each Edge and then filling in the Middle with squares or something now the other two phases probably have some illegal angles but with a little trick we can actually construct them correctly anyways if we look at the angles that are touching the front face we can fill them in by hiding the excess of the slope under the face we already made the other angles of the face will still have to be above 26.