What's New in ORTEP-III

For compatibility with existing ORTEP data sets, ORTEP-III retains ALL the functionality of OR TEP-II, released in 1976. New capabilities include:

Further details on many of these items may be found in the Overview and Operation section of the Online Documentation.

User Interface

ORTEP-III is a semi-interactive program that requests certain information from the user while the program executes. A default value for each item requested is provided in square brackets, and it will be used if the user simply hits the RETURN key (on some keyboards, the name of this key is ENTER). On systems that distinguish upper and lower case, care must be taken when entering file names to provide the correct case of the letters.

Screen Display

The screen drawing subroutines available in ORTEP-III use PGPLOT. PGPLOT is a free graphics library developed by T. J. Pearson at the California Institute of Technology. The package is written in FORTRAN and operates on a variety of platforms. Information about PGPLOT can be found on the World Wide Web at http://astro.caltech.edu/~tjp/pgplot or via e-mail to tjp@astro.caltech.edu.

Output Formats

Illustrations generated by ORTEP-III can be saved as Encapsulated Postscript or Hewlett-Packard Graphics Language (HPGL/2) files. The files may be printed directly on a wide variety of printers and plotters or may be imported into a number of computer programs that accept these formats.


By default, ORTEP-III plots its illustrations in black on a white background. The new 204 instruction allows color to be added to the illustrations if the output device supports color. Once a color is set, it remains in effect until another 204 instruction changes the color. A 204 with no parameter (or a "0") returns the plotting color to black (or pen #1). The screen and Postscript drivers built into ORTEP-III define color value 2 as red, 3 as green, 4 as blue, 5 as cyan, 6 as magenta, and 7 as yellow.

Interactive Editor

ORTEP-III provides a simple line editor for editing the input file without exiting the program. When the editor is invoked, the instruction set from the input file is displayed on the screen with line numbers (#) along with the editor commands.

C=Change line #                         D=Delete line(s) # [#]
I=Insert line before #                  T=Type line(s) [#] [#]
S=Save modified instruction set         O=Restore original instruction set
P=Save drawing as Postscript            H=Save drawing as HPGL
R=Redraw structure on screen            Q=Quit


In previous versions of ORTEP, Format No. 3 trailer cards were the only means of placing comments in the input file. This method still works in ORTEP-III, but a new method also exists. Among the ORTEP instructions, any line beginning with # is treated as a comment and is totally ignored by the program. Such comments can only go in the instruction portion of the input data and only at places where a new instruction could begin, i.e., comments can not go between instructions and their trailer (continuation) cards. CAUTION: These comment lines are not printed in the ORTEP output file, and they are lost if the input file is edited with ORTEP-III's line editor.

Alternate Formats for Atomic Parameters

ORTEP-III provides a way to input atom parameters that are available in a "nonstandard" format. If the sentinel value (column 1) on the last symmetry card in the ORTEP input file is "2" instead of "1", the program asks the user for the name of a file containing the atom parameters and branches to subroutine READIN to read the information. This subroutine may be recoded to read any desired format.

Atom "Features"

In earlier versions of ORTEP, atoms could be referenced only by their numeric positions in the input file; and atom number runs (ANR) were used to select groups of atoms to be treated in the same manner. ORTEP-III allows two optional attributes called "features" to be included with each atom, and feature number runs (FNR) can be used to select groups of atoms having particular features. To handle features, a new parameter, number run type, has been added to the 100 series, 400 series, 505, 506, 700 series, 800 series, and 1001 instructions. Features should prove especially useful for polymeric materials such as proteins or nucleic acids and for critical net illustrations.

Critical Net Illustrations

ORTEP-III can produce critical net illustrations that depict some canonical topological characteristics of the global ensemble of overlapping atomic-thermal-motion Gaussian density functions in a crystal. Click here for examples.

Symmetry Operators

The symmetry operators in the ORTEP input file may now be provided in a free format using the xyz coordinate triplet notation found in the International Tables for Crystallography. ORTEP is informed that this style for the symmetry operators is being used by having a "1" in column 1 of the cell parameter card. (A "0" or blank in that position indicates the old style is being used.)

Symmetry cards using this style do not have a specific format with the following two exceptions: (1) the symmetry information on each card must not go beyond column 72, and (2) column 1 must be blank on all symmetry cards other than the last one in the set, which must have a non-zero value in column 1. Below is an example set of symmetry cards to illustrate the flexibility of this style.

             X   -Y   Z+1/2
             X+0.5,  .5+Y,  Z

As shown, letters may be either upper or lower case. Commas or spaces may be used to separate the components of the triplet. The three components may not have spaces within them. Decimal fractions may be used with or without an initial 0. Fractions may precede or follow the letters.



Page last revised: April 12, 1996