Modeling a Low-Poly Medieval Vault

In this tutorial, I'll explain how I made the four way vault that is is the basis for my low poly castle. The screen-shots in this tutorial are from Blender 3d, but the modeling principles will be the same in any 3d package. Click the images to enlarge. The shortcut keys I'll be naming are based on Blender 2.5 series.


Step 1: Fire up blender, and set this  image as your background:

Step 2: Create this shape. It's best if you model one half, then duplicate and flip the verts horizontally. Be sure to join the 2 verts at the top of the arch. Re-size your arch to 4 blender units wide.

Step 3: In top view, extrude all the verts in the Y direction 4 Blender units. From the top, you should see a 4 x 4 square.

You should end up with this:

Step 4:  Enter top view, object mode. Select the arch and duplicate it. Rotate it 90 degrees:

Enter front view, and make sure the duplicated arch is still the active object.

Step 5: Enter edit mode, select all the verts on 1 side, and move them 1/2 Blender unit to the side (.5 in the x direction). The result should look like this:

Step 6: For this step, be sure that you are in wire mode. Blender can't see through shaded shapes when selecting verts. Select the top vert opposite the side you just moved 1/2 blender unit - the left side in this case - and drag it in the x direction until it lines up with the top of the first arch. If this sounds confusing, take a look at the next few images and you'll see what we are shooting for.

Continue selecting verts (use "C" circle select to make sure that you grab both verts), and moving them so that they line up with the template arch. Be really careful here, and make sure that your verts line up with the other arch exactly. Zoom in really close, or you'll be sorry later. The result should look like this:

Take a look at your progress in perspective mode. You should have something like this:

Move the original arch out of the way for now. You can use it as a straight hall way section, as it will connect with the 4 way arch we are making perfectly. You should end up with this - 1/4 of our finished 4 way arch:

Step 7: Go into top view, edit mode. Place the object center exactly at the point of the arch. Select all the verts, and rotate 90 degrees, with this result:

Step 8: Merge these verts by selecting all then removing doubles, or use center select to select the 2 verts near each other, then Ctrl M, center to merge them.You'll likely use a combination of both techniques.

Step 9: Making certain that you've got no double verts, head back to top view, select all, and rotate 90 degrees, with this result:

 

As before, remove all the double verts, any way you like. You should end up with this:

Step 10: Make sure all of your face normals point inward, thus:

Next, set the whole arch smooth, and add an edge split modifier (but don't apply it). The default 30 degrees is fine.

That's the basic 4 way arch. If you like, you can duplicate it and join the verts as before. When you join 4 together, you'll end up with this result:

The resulting geometry has some faces we don't need. Select the offending edge loops as below, and delete (delete  - edge loop).

After unnecessary edge loop removal, you'll end up with this:

At this point, you've got a hallway and a vault pattern you can use to create vaulted rooms of any size. In the next tutorial, I'll explain the construction of an arched doorway. Enjoy!