[en] 1 - Description of program or function: PLOT3D is a general purpose, interactive program, designed to draw three dimensional graphs, histograms, maps and stereo 3D plots, in single or multicolour, from arrays of points (x,y,z) under various options such as clipping, smoothening, shading, etc. using a built-in 3D interpolation function, and after arbitrary rotations about the three coordinate axes. 2 - Method of solution: For plotting a two variables dependent function, z(x,y) the program reads its z values in form of a matrix, z(i,j), in which the indices i and j specify the values of x and y, respectively, either by direct proportionality or through array variables, X(i) and Y(j). Thereafter, the program normalizes the data coordinates, transforms them to effect the orientation of the figure, and then draws axonometric projection using single floating horizon method for hidden lines elimination. In addition, a built-in 3D interpolation function allows numerous intermediate points to be generated and immediately plotted and thus helps in drawing 3D histograms or smoothening the plotted surface, and in shading. The program has two modes of hidden lines removal, both based on single floating horizon method. There exist five versions of this program as listed in item 7. 3 - Restrictions on the complexity of the problem: The size of z data matrix cannot exceed 115 x 115. The number of interpolations cannot exceed 1001 x 1001. In versions 4 and 5, the number of colours cannot exceed 16. In layout diagrams, the items cannot be anything but orthorhombic in shape