Imprinting has its own classifications that further define the problem. Models often exhibit combinations of these different situations when trying to sort out the sweep paths between pairs of source face(s).

When selecting source faces, it is important to recognize that the pairs of source faces need to have proper matches (that is, each level must be resolved with other levels). If source faces cannot be paired, imprinting must be done by the software to create proper pairs. The software supports only certain types of imprinting, so it is important to understand these cases.

It is also important to note that if you set the Free Mesh Type to anything other than Not Allowed, some of the imprinting will not be done, as this can lead to some problems in the creation of the free blocks. For example, on some models you could get a pure hex mesh if you set Free Mesh Type to Not Allowed, but not get a pure hex mesh if you set Free Mesh Type to some other value.