Geometrically perfect vaulted arches

A vaulted arch is made from two circular arcs that intersect like this:

Original source here…

A structure like this can be created in Dromed using cylinders.

Create a FillAir cuboid. 8 x 8 in this example:

Create a cylinder. 24 sides, aligned by vertices. Its diameter should be at least double that of the cuboid’s width. Make sure the edge of the cylinder meets the opposite corner of the cuboid. Type: Solid → Water. FillWater works okay too, but may cause problems with other terrain, or if the arch is next to a corner:

Clone the cylinder and change it to Evaporate. Move it to the other side so its edge meets the other corner of the cuboid:

Make a clone of the first cylinder, and change it to Water → Solid:

When you optimize you will get this texture problem if these brushes use a different texture to that of the wall. This is because the ends of the cylinders are flush with the wall. You can either extend them a little, or just change those end textures:

If you want to use a different texture along the back of the arch, e.g. to place a window texture, remember that you have three brushes all sharing that face, so change the textures of them all:

Optimize:

Change the other two:

It’s nice for arches to have a solid frame. Fortunately that’s also possible with this method.

Start with the outside. Note that this sticks out of the wall:

The first cylinder should be Flood, and once again, at least double the size of the cuboid:

Clone it and move it across. Change it to Water → Solid:

Clone the first one and make it Evaporate:

The result is a solid vaulted arch sticking out of the wall:

The inside can be made using the first method, but with one little difference. Once again, start with a FillAir cuboid:

The edge should line up with the corner of the FillAir cuboid, and the centre should line up with the center of the larger cylinder:

The second cylinder is the same, but on the other side:

Clone the first of the ‘inside’ cylinders, and make it Water → Solid:

The frame does not have to stick out, but if it does you’ll end up with this effect:

A lot of people ignore things like that, but you’ll win an award for decency if you put a little solid brush there to correct it:

You can make the pointed section taller by increasing the sizes of the cylinders, as long as their edges line up with the corners of the cuboid:

When the cylinders are so large they cut into the ground, there will be a little nick in the ground, which will need to be filled in with a solid brush:

This image shows the complete build order. To build without the frame, start at 5:

Despite the size of the cylinders, you can build mulitple arches very close together as long as you make one complete arch at a time:

It does get a little hard to see what’s going on, but it’s a price worth paying for perfect vaulted arches.

Many people will prefer to use wedges. The advantage of wedges is that they are more compact, whereas you can see the cylinders extend way beyond the edges of the archway. Cylinders on the other hand don’t require much resizing and do not require too much tinkering with the grid size.