Computer plotting program PLOT 3D draws views of surface forms z = f(x,y). Surface thus defined by program may be drawn after arbitrary rotations. Program portrays behavior of various functions involving two variables in many engineering, physics, and mathematical relationships

Canright, R. B., Jr.

Swigert, P.

English

NASA Technical Reports Server

May1972	 CORRECTED COPY
	 .B72-10253 
S NASA TECH BRIEF Lewis Research Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Computer Program Draws Three-Dimensional Surfaces 
..
The problem: 
Many fields such as mathematics, physics, and engi-
neering are concerned with the study of functions with 
two variables. These functions are conventionally repre-
sented by tables or crossplots, both of which are diffi-
cult to use. Three dimensional plots of these functions 
are easier to analyze. 
The solution: 
A computer plotting program, PLOT31), can draw 
views of any three dimensional surface which is of the 
form z=f (x,y). Inputs to PLOT31) are the function f 
and bounding values for x and y. The surface thus de-
fined by PLOT3D may be drawn after arbitrary rota-
tions. Output is by off-line incremental plotter or on-
line microfilm recorder. 
How it's done: 
Several computer programs for plotting three-dimen
-
sional surfaces have been developed elsewhere. Each has 
its advantages and limitations. Some are intended pri-
marily to show the spatial relationships among solids; 
others draw surfaces made up of data points (such as 
programs to draw contour maps). PLOT31) will plot any 
function of the form z=f (x,y). The program calculates 
the function for a range of values of the two independent 
variables, defming the surface. Rotated views of the sur-
face are made by simple matrix operations. 
Notes: 
1. This program is written in FORTRAN IV for use on 
both the IBM 7044/7094 direct-coupled computer 
and the IBM 360/67 computer. 
2. With curve fits, PLOT31) has drawn experimental 
data, and has been used to make motion pictures and 
illustrations.
3. The output drawings are presently on graph paper 
or microfilm, but the program can be adapted to 
other media, for example, an oscilloscope. 
4. PLOT31) can portray the behavior of various functions 
involving two variables such as in the following engi-
neering, physics, and mathematical relationships: 
a. phase diagrams and equations of state for thermo-
dynamics; 
b. energy surfaces and potential wells in mechanics; 
and 
c. mapping of the analytical and numerical solutions 
of partial differential equations found in heat 
flow, electricity and magnetism, fluid dynamics, 
and quantum mechanics. 
5. Requests for further information may be directed to: 
COSMIC 
112 Barrow Hall 
University of Georgia 
Athens, Georgia 30601 
Reference: LEW-1 0482 
6. The following documentation is available from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $6.00 
(or microfiche $0.95) 
Reference: NASA TMX-1598 (N68-28240), 
PLOT31) - A Package of FORTRAN Subpro-
grams to Draw Three-Dimensional Surfaces 
Patent status: 
No patent action is contemplated by NASA. 
Source: R. B. Canright, Jr., and P. Swigert

Lewis Research Center

(LEW-1 0482) 
Category 09 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Computer program draws three-dimensional surfaces

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