I have discussed the way I learned to look at roof framing in another thread. I thought that I would put up a little information to clarify what it is I am talking about exactly.

There are 2 ways that roof framing is categorized in Switzerland and, as far as I am aware, most German-language discussions of the topic. Roof are categorized based on the nature of the rafters, whether they be hung from a ridge beam or seated into a tie beam. The two roofs are described as being 'Hanging' or 'Standing'

In Switzerland, the name for a rafter distinguishes between these forms. If the rafter is hanging and unseated at its bottom, it is called a "Rafen" if it is standing and seated into a tie beam (which is the familiar method in North America) it is called a "Sparren". I am not aware of whether or not this same convention is repeated in Germany, I don't believe it is, at least not universally.

Most roofs, in reality, combine the two methods in some way or another. But a few general rules apply. First, a 'Sparrendach' or standing type roof never has a structural ridge beam. There may be a ridge present, but it only serves as a means of securing the rafters relative to each other. Rafter-framed roofs generally employ a high collar to tie brace the rafters pairs. On a 'Rafendach' there is usually a structural ridge. at the very least, the uppermost supports can be no lower than the top third point. Combined methods see things like, 'Rafen" roof supported by truss-type assemblies (thus necessitating a tie beam) and "Sparren" roof structures with direct-posted purlin supports.
The logical conclusion of the 'Sparren' method would be truss construction, as is seen in England. This conclusion was not arrived at in Switzerland. True trusses, as we are accustomed to using the term in reference to Timber Frame roof construction, is not used.
This makes a contrast to American roof framing where we are accustomed to classifying the roof structure into the categories of 'Truss Support' and 'Purlin Support' both relying on standing rafter construction (and truss supported roofs often employing common purlins)

Most American roof framing would fall into the 'Sparrendach' category, as it relies on rafters seated into the plate or into the tie beams.

Here is a bit I translated out of German, comparing the two:

There are 2 different categories that we can use to describe the roof construction in our land: On one hand there is the hanging roof supported by purlins, and on the other hand is the standing roof of rafter construction. We will compare the common features of each. Today, however, the distinction between the two is not always so sharp, but without this distinction we cannot clearly describe roof framing.

Pfettendach

Also Called “Rafendach”
The roof is supported by posts or directly by the walls

Roof beams parallel to the ridge (pfetten, purlins) support the rafters that are hung from above, on which the roof covering lays.

The roof is ‘Hanging’
A ridge beam is necessary

A cross-beam (Trämbalke) secured the eaves walls of a timber framed structure from working inward under the pressure of the roof.
The roof is ‘Drücklastig’

The rafters are hung from the ridge beam singly or in pairs.

The rafter lay atop purlins at the foot of the roof structure, mostly unfastened to them.

The roof pitch can be flat or steep

Sparrendach

Also called a ‘Kehlbalkendach’
The roof is supported independent of the walls by a separate construction

Free-standing roof beams (Sparren, rafters) are bound together in pairs and stand firmly on a cross beam (Anchor or Tie beam)

The roof is ‘standing’
A ridge beam is not needed

An anchor- or tie-beam holds the outward thrust of the the rafters.
The roof is ‘Schublastig’

At the ridge the rafters are secured fast to each other.

The rafters are joined fast to the tie beam at the foot of the roof structure.

The roof pitch is always relatively steep so that the outward thrust is not too great.

DL, you are a wealth of knowledge. And I'd like to take this opportunity to thank you for the simplicity and thoroughness of your scholarship on these topics, especially in light of the normal very low signal-to-noise ratio that we usually encounter on internet info sharing sites.

OK, enough praise-singing. Can you elaborate on this phrase a bit? It's the only part of the Rafendach system that's not clear to me.

"A cross-beam (Trämbalke) secured the eaves walls of a timber framed structure from working inward under the pressure of the roof. The roof is ‘Drücklastig’"

Certainly,

First of all, this points out this assembly is specific to a structure with timber framed walls. Such roof framing is common on log buildings and also known on stone walled structures. In these, the nature of the walls more or less eliminates the need for such a cross beam. Timber framed walls, being naturally unstable, require cross beams to brace against the pressure of the rafters. In a log structure, for example, you would just put the rafters directly on top of the log walls and trust that the partitioning walls are sufficient to brace the structure against the inward pressure.

This is a direct comparison to a roof with no ridge and seated rafters. Such a roof as discussed has an anchor beam or tie beam designed to resist outward thrust.
The 'Drücklastig' roof instead has a simple cross beam that braces the walls against inward-working of the rafters.

To resist inward pressure, all you need is a stick to push against it (remember Newton's third law) whereas to resist roof thrust, you need a heavy beam with complex tension joinery.

Drücklastig = inward working (literally, press-loaded)
Schublastig = outward working (literally, thrust-loaded)

So we can think of things in terms of 'Rafter pressure' or 'Rafter Thrust'