Every photograph here is a real bay window cushion made to measure, read line by line by one of the seven masters. For sizes, foam and fabric, start at the Cushion Atlas page.
Which side does the zipper go on for a trapezoid cushion?
The workshop's answer
On request, the workshop puts it on the shorter back edge, the D edge for example, so the long front edge stays clean. Note it on your drawing or in the order note.
How thick should a window seat cushion be so it doesn't ride up over the window?
The workshop's answer
For a narrow window seat the workshop suggested 2 or 3 in (5 or 8 cm), and it confirms the final thickness with you before production. Measure the height available under the window frame first.
In a review photo the cushion looks like velvet, but the swatch looks like leather. Which fabric is it, and is it right for me?
The workshop's answer
That cushion was made in G-42, a leather-textured, highly durable pet-friendly fabric chosen by a customer with a large dog to prevent damage. Without pets, the workshop recommends the Soft or Velvet collections instead: more comfortable for daily use, in very similar colors.