AutoCad is one of the most famous computer programs for computer designing and drafting. The author of the program is the company Autodesk which offers over 75 specialized software tools and aids for different expert fields (mechanical engineering, electrics, electronics, civil engineering, architecture, cartography, geodesy, etc.). The basic program – AutoCad – is a sophisticated, designing tool of wide, you could say universal, purpose which supports two-dimensional designing, which basically replaces classic designing on paper, i.e. drawing board, divider, ruler, and three-dimensional modeling of complex objects which, in model space, can be zoomed in, bent over, turned, shown in different projections, angles and cross sections from all directions, with perspective effect or without it, illuminate at will and render it, so that the 3D display imitates the photography of a virtual object which exists only in the computer memory. Unlike the alternative software products for 2D and 3D modeling, AutoCad is specific for its sophisticated (perhaps even too complicated) system of sizing and high precision which can go under milimicrons and a system of setting dimensions and measurements with automatic calculations satisfying even the highest technical standards. With certain conditions, setting dimensions is associative, i.e. it automatically adjusts to the changes in geometry of the processed model.

3D – Three dimensional regime
The space for modeling and workspace in the regime “model” make “the model space”, in which a three dimensional model is defined (constructed, changed, sized and described). In workspaces in the regime “model”, projections can be opened on every plain or cross section and views from any direction of the three dimensional model can be seen. The model and projection space in workspaces automatedly cooperate, so that every change in any work space or on the model in model space reflects on the model, i.e. it is automatically updated on all other work sheets. Model space is unlimited, and a model can be zoomed in without limits in the direction of the widening and enlargements of details can be made without losing the precision of size or resolution.