Just a simple question I have.
Is it possible to make a game much like more recent Sonic games where some parts are in a 3D perspective while others are in 2.5D?
And if so, how could I do so? Is it as simple as making a sidescroller project and copying its files to the 3D project, or is it more complex than that?
Everything is “done in 3D”
If you do not want perspective, you can use an ortographic camera (ie. “2D”). Even then you will be able to rotate things and do 3d stuff.
2.5D you are meaning parallax scrolling? you have to implement it yourself but it should be pretty easy.
short answer: yes, you can achieve what you want but you will have to implement the parallax scrolling yourself (just assign a different speed depending on depth)
I’m going to assume that by 2.5d you mean still 3D with the movement constrained to 2 dimensions.
In that case you could use something as simple as this to change between the different styles of gameplay. I’ve just re-purposed the movement inputs to do different things in either view. Apart from this, just disable mouse look in 2d and you’re good to go.
Note: You should also constrain movement to a plane for 2d bits and/or lock movement on whatever axis you don’t want to move on and do the usual things for making 2d stuff.