1560 PATTERN LAYOUTS
As several has probably read, the cut for the velvet Pisa dress and Eleonora di Toledo's satin funeral dress are very similar. They're actually so similar it has been suggested they're both made by the same tailor, Master Agostino.
As they layouts above shows, there are indeed great similarities. The skirts are made up of 4 straight panels with gores inserted at the sides. The back panels are longer to allow a train; the Pisa one seems a tad shorter but they both have long trains. There is slight differences in the gores; the Pisa dress has three on each side opposed to two in EdT's dress. But the general idea is the same, and it also correspond with what's seen in Juan Alcega's tailor book from 1589. This is for example Jennifer Thompson's draft of his "kirtle for a fat woman":
http://www.festiveattyre.com/research/diary2002/images/skirt2.gif
Both skirts have the (in)famous tuck at the lower hem, and the hem is also stiffened with wool felt on the inside as well as decorative trims on the outside. They also both have a vertical strip of trim down the skirt front.
The dress fronts of Eleonora's funeral dress and the crimson Pisa dress.
The bodices also correspond with eachother. Both are fairly square, with a pointed front, and with side/back lacing. The shoulder straps have about the same placement and they're of the same width. Biggest difference here is that Eleonora's bodice seems to have been longer both in front and in the back. She might have had a longer torso than the wearer of the crimson velvet dress. It's not possible to tell from the drafts, but the Pisa dress also have the lacing further to the side than the EdT one. The trims are similarly distributed, except Eleonora's dress also had the V shape in the back of the bodice. The Pisa dress doesn't.
The bodice backs of Eleonora's funeral dress and the crimson Pisa dress.
A big difference is that in EdT's dress the skirt front is cut after pleating, to remove as much of the extra fabric as possible. This accounts for the pointed shape of the upper line. This doesn't seem to have been done on the Pisa dress, as it is more gathered than pleated in fromt (although the draft above is how they assumed it was originally and not a draft of the dress after the many remodelings and restorations).
There are other differences too: EdT's dress have one broad embroidered trim, the Pisa one have two narrower rows of trims. The latter also has sleeves, something Eleonora's funeral dress probably didn't have (there are no traces of lacing or similar at the shoulders). The Pisa one is made of crimson velvet, while the funeral dress was of white (some say yellow, I go with "Moda a Firenze" here) satin. But these differences are to be expected, just like no-one dresses identical today. Variations depended on the wishes of the client, the occasion the attire was meant for, and of course of the physical shape of the wearer.
So yeah, if you've read that these dresses are similar in cut but never seen it, these layouts shows how similar they actually are. Both sketches were made by Thessy Schoenholzer Nichols and included in the 2000 book "L'abito della Granduchessa".