Masonry Arch

Masonry Arch: Check this box, then choose a style for the arch from the drop-down menu. The rest of the controls vary depending on the arch you choose here.
Rise: The value of the arch’s rise.
Skewback angle: For “Jack” arch styles.
Type: Choose Stucco or Brick. If you choose Brick, you can set values for the Brick and Mortar thicknesses below.
Note: Using brick arches in a large number of windows may increase your model size significantly.
Keystone: For arch styles with a keystone, set values for its width, oversize (if the keystone extends vertically above the arch) and projection (if it protrudes horizontally from arch).
Arch on Header: Check this box to place the arch directly atop the opening header.
Niche below Arch: Check this box to create a niche (or inset) beneath the arch.
Horizontal Overhang: Use the two fields on either side of the drawing to define the arch overhang on the right and left side of the opening.