Need help making a cross-shaped tunnel system with another tunnel on top

[Edddd_64 (Silly Goofy Guy III)]

Im attempting to make a same model/map as the concept art shown below,

The way I attempted doing this in 3d was beveling a hallway on top until it gave me the arch-shape. I duplicated it 4 times in the same object (object mode) and I don’t know how or if this is how I should connect them.

[Zebrahead]

Hi,
i would start with a cross shape like this:

Give the blue edges a bevel weight of 1.0

Then add a new Foat Edge attribute (you can call it whatever you want) and set the value for the yellow edges to 1.0:

Now add two bevel modifiers: one for the outer (blue) and one for the inner edges (yellow):

Hope that helps!

[Okidoki]

You can also use the bridge tool to connect two half of one tunnel, but you might have to cut the lower half… in half .

You can choose the “curvation” to you liking… or even not (and directly connect it). Then moving some vetices to the middle ( scale restricted to XY with pivot point to 3D cursor S Shift Z) and copy and rotate… do not forget to merge by distance… (or repeat above workflow for every tunnel turn).

[Edddd_64 (Silly Goofy Guy III)]

Hi, I appreciate the help but how would I create a cross shape such as that? I attempted bridging the 4 faces of 4 rectangles facing eachother but that just got me weird topology.

[SoundDifferent]

You can create a “cross” like topology on top, and then bevel edges marked green.

[Zebrahead]

There are probably a lot of different ways to do this…
For example:

Start with this shape here:

Select the face in the center, Right Click → Subdivide:

Select these 5 points, press M → At Center:

Et voila: