This is a 3D model of a section of the nave of a Gothic church.

I based the height to width ratio on the golden section,and the design of the arches on the basic Gothic proportions, so nothing very new. I hope to add the side alleys and some flying buttresses in a later version.

The only clever trick is the use of little cross-shaped pieces to hold the two parts of the pillars together, one at the base, and one at the top, resting on a little shelf. Since the pillar parts that slot into each other are rather long, you need this trick to keep them from sliding side to side.

I don't have a laser, so I've never actually made this thing. [Edit: but I have made a smaller variant which assembled just fine, see below] I designed it in Sketchup, which worked well to see how pieces work together.

I think it fits together fine (if made from a 12"x12" piece of 1/4" thick acrylic or plywood) but I don't know how to calculate the kerf on the cuts... so this may need some adjustments to cut properly. Sorry for any waste of time and material... :-(

As for assembly, you will need to make at least two sets of parts to make a single nave section (four pillars and all the attendant arches). If you make more, you will notice that you are making more pillars than you need, so there will be some waste.

The pillars pieces slot into each other, and the cross pieces slide over the X thus formed and rest on the little shelf at the bottom.

Same idea at the top of the pillar, just pick a cross piece with the diagonal slots. The arch pieces should drop into the top cross piece, and there are little connector parts to join the arch halves at the top, like keystones.

Refer to the assembled pix for guidance, it should be relatively easy to figure out.