If a cover is made in InDesign correctly for press, then there will be 3–7 pages and then the pdf is created as a spread with a certain amount of bleed necessary for the printer. Some printers might require 5mm of bleed, some might require significantly more. This technique will also created crop and fold marks for the printer which will be outside the bleed area although some printers prefer no crop and fold marks. This is of course irrelevant for boxshot :-)
It would be very nice if Boxshot could “read” the fact that there is bleed on the pdf and use the amount of bleed necessary to fold over the edge of the book. So if there is 20mm bleed, but boxshot only needs 5mm for the distance between the hard cover and the book block and another 1mm to wrap over the top of the cover, then it would only use 6mm of the 20mm bleed. If only 5mm bleed has been provided then of course the file would be be press-ready!
If there is no bleed, then Boxshot would simply revert to stretching the artwork as it currently does.
The reason why I bring this is up is because I showed my client a 3D render and he noticed that the text on the spine, even though it looked fine in the PDF was too close to the top of the spine of the book.
Customer support service by UserEcho