The previous post about mecha design was all about the basic ideas that yours truly tends to use when it comes to transforming or shape changing robots. As mentioned, they are not definitive and many would probably contest them, but they work just as well. However, all transforming mecha follow one essential thought pattern most of the time; from inhuman shape to humanoid shape. This shape can be whatever. Cars, planes, guns, dinosaurs, trains… pretty much everything has been turned into a robot. Hell, there used to be a saying on imageboards that the Japanese can transform anything into a mecha if they just want to. Of course, there are those that simply change utility shape between modes and never become humanoid. These are relatively rarer in scale of things, but the overall discussion follows the same pattern overall. You have a shape that you want to force into another.
The title of this post is misleading. The term that I should be using is cuboid. However, I am going to break any and all good language practices and keep mixing cube and cuboid to label any cuboid shapes. This would an example of marketing of sorts when you get down to it, as many companies want to use cube in a similar sense. Nintendo’s Game Cube being one, with it being a cuboid even when the Game Boy player is attached.
As with any matter like this, there is no one correct way to do anything. The examples here are simply just for the sake of examples and being as simple as possible. Expanding on basics and building on them is really the only way to get around.
The core idea is to take a cube and “spread” it to the similar breakdown as human would be, if we’d draw human with simple geometric shapes.