Fixed Tool Turning is the ornamental turning term for scraping.
If you've used scrapers in wood turning, you get the idea: a metal tool with some profile is presented to the object whilst the object turns, and the tool scrapes off a very thin layer at a time.
The shape of the scraping tool used in ornamental turning is a bit different than the one shown above as, in ornamental turning, the tool will need to be able to get into cracks and crevices created by the rosette. A bevel angle of 20-22° is typical, and 15° is not uncommon.
There are some shapes that can only be made using this method of turning.
Guilloché is another form of fixed tool work, but the tool is applied to the material in a slightly different different manner (typically the tool is spring-loaded).
GPhilPoirer made this video of fixed tool work on his Armbruster Mark II rose engine late, and posted on his Instagram feed.
How many times did you rewatch it, mesmerized by the actions?
This video describes tools, setup, and turning process to produce patterns that are only available with fixed tools. It was given by Al Collins at the 2018 Ornamental Turners International Symposium. This is fascinating to watch, as it happens so very slowly.