  Applying the modular technology of developing of the problem-oriented
extensions of a CAD system to a problem of automation of creating of the
axonometric piping diagrams on an example of the program system TechnoCAD
GlassX is described. The proximity of composition of the schemas is detected
for special technological pipe lines, systems of a water line and water drain,
heating, heat supply, ventilating, air conditioning. The structured parametric
representation of the schemas, including properties of objects, their link,
common settings, settings by default and the special links of compatibility is
reviewed.
