Please note that this thread is intended to be directed towards the audiences owning Pokemon Platinum, as this may only be testable on Pokemon Platinum.
Go away!
Alright, so we know we can get into the void in Pokemon Platinum, but we can't get out of the initial void (in this case, I'll be using the Poketch Co. as an example). This means that we can get into the void by going downward, but we can't go anywhere else, i.e. Jubilife T.V., Turnback Cave, etc., because of the webs.
Web: A space in the void where, if walked into, you can walk neither up, down, left, or right.
Through a little bit of testing, I've found that there are webs all along the top of and to the left of the Poketch Co. building, and there are no webs to the right of or below the Poketch Co. building. However, one very notable thing about the Poketch Co. initial void is that it has a Mystery Zone just before the webs on the left wall, all the way at the bottom. This Mystery Zone has, going from right to left, 9 walkable tiles, 1 surfable tile, then 17 walkable tiles, which then you come to an invisible wall (not a web), and you cannot walk upwards while in the Mystery Zone, except when you are at the very right, to enter the Poketch Void from where you entered the Mystery Zone.
However, I have found a way to bypass the webs on the left, finding that the Poketch Co. void spans exactly 63 tiles horizontally. First, you need to go to the Mystery Zone, which is, from the doorway of the Poketch Co., 1 step South, 17 steps West, 18 steps South. Now you should be in the aforementioned Mystery Zone. Now, to go above the Mystery Zone, or get past the western wall of webs, go 1 step North from the Mystery Zone, open your Pokedex/Pokemon/Bag/Trainer Case/Options/Town Map, go 1 step South, 1 step West, and you should now be able to go 1 step North. Congrats, you've now bypassed the wall of webs to the left of the Poketch Co. building. However, there are still webs on top of the Poketch Co. bulding and you've now created a wall of webs to the right of your location (where the previous webs were).
Now, all we need to do is find a way to either open the Pokedex, etc. somewhere that will open up a pathway exiting the initial void, or, what this thread is about, Tweak the void to get past the walls/webs.
Any questions, comments, or whatever, just post here.