Specialists performing unusual decorating facades
Plaster is an atypical type of decoration in modern living rooms or offices. There is no doubt that the years of its heyday is long behind him, but does not change the fact that there is still a lot of people decide to use this technique in his apartment. In each urban area can find at least a few companies specializing in this field, so we should not have a problem with that if you choose such treatment at his home. Just use the search engine.
Coving definition
Molding, or moulding (Commonwealth), also known as coving (UK, Australia), is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster, but may be made from plastic or reformed wood. In classical architecture and sculpture, the molding is often carved in marble or other stones.
A "sprung" molding has bevelled edges that allow mounting between two non-parallel planes (such as a wall and a ceiling), with an open space behind the molding. Other types of molding are referred to as "plain".
Źródło: https://en.wikipedia.org/wiki/Molding_(decorative)
About ceilings
Ceilings are classified according to their appearance or construction. A cathedral ceiling is any tall ceiling area similar to those in a church. A dropped ceiling is one in which the finished surface is constructed anywhere from a few inches or centimetres to several feet or a few metres below the structure above it. This may be done for aesthetic purposes, such as achieving a desirable ceiling height; or practical purposes such as acoustic damping or providing a space for HVAC or piping. An inverse of this would be a raised floor. A concave or barrel-shaped ceiling is curved or rounded upward, usually for visual or acoustical value, while a coffered ceiling is divided into a grid of recessed square or octagonal panels, also called a "lacunar ceiling". A cove ceiling uses a curved plaster transition between wall and ceiling; it is named for cove molding, a molding with a concave curve.1 A stretched ceiling (or stretch ceiling) uses a number of individual panels using material such as PVC fixed to a permieter rail.
Źródło: https://en.wikipedia.org/wiki/Ceiling#Types