You're looking for a doom kind of style so i recommend to look for doom making tutorials also I think that you could possible make an object(create floor and roof in 3d in it look up the info game maker studio gives you about 3D) and if you can make another object wall make your 3D blok in it and you just place the blok on the map where you can like you would with a tile and just represent is by a sprite or somthing(and make the cube the same length). For the floor and roof you cool use a for loop to draw cubes on another Z position or just use a flat sprite or somthing or flat shape as roof. I've never done 3D in game maker studio but I don't think it is that complicated as for the kind of game you want to make.
d3d_start(); //This code has been placed in the create event of an instance to tell
GameMaker: Studio that all further drawing should be done in 3D mode.
d3d_draw_block(x1, y1, z1, x2, y2, z2, tex, hrepeat, vrepeat)
x1 The initial x coordinate of the block.
y1 The initial y coordinate of the block.
z1 The initial z coordinate of the block.
x2 The opposite x coordinate of the block.
y2 The opposite y coordinate of the block.
z2 The opposite z coordinate of the block.
tex The id of the texture to use (-1 for no texture)
hrepeat Amount of horizontal repetitions for the texture.
vrepeat Amount of vertical repetitions for the texture
d3d_set_projection(100, 100, 10, 200, 100, 10, 0, 0, 1);
The above code creates a typical first person shooter view.
extra info about projection:
Often in 3D games you want to change how you look at the world. For example, in a first person shooter you probably want to have the camera look from a position a bit above the xy-plane along the xy-plane, which, in graphics terms, involves setting the correct
projection. This projection should be set in an instance that is created before all other instances (you can set this from the
Instance Order window in the
Room Editor), and it should be at a very low depth so that is drawn before all other instances in your room, otherwise you will get issues when drawing.
NOTE When GameMaker starts drawing a room it will set the view point back to the default position, so the first thing you must do when drawing the scene is set is to the projection you want. This must be done in the draw event of an instance!
For the 2D graphics GUI just draw your stuff on the DRAW GUI layer
See game maker studio can handle this
!