I had some fun taking pictures of the Gothic cross grain vaults in St.Martin, Heiligenstadt. They make for interesting effects.
The arcs of the vaults are not rounded like in the Romanesque style, but pointed at the center. During the development of the Gothic style the pointed structure gets more angular and steep, abandoning the form of a true arc. View to main nave from the north aisle.
The main nave looks higher than it is because of the unadorned walls. They are often structured by ornaments in other churches. The heavy 'bundled pillars' that divide the aisles from the main nave add to the effect. The aisles are more like rooms of their own here than in some other churches I've seen. Choir
I got a bit artsy with that one and went for an odd angle.
The crypt below must have belonged to an older church and was intergrated into the Gothic building. St. Martin, crypt from about 1250
It is not clearly to be seen in the photos because of the angles, but this one shows an earlier stage where the rounded Romanesque style you may remember from Lippoldsberg
(last picture in that post) just started to develop into the Gothic one. If you compare the vaults of the crypt with the arc on the second picture, you can see a slight difference.