Unigraphics Primer

Ari Requicha
January 28, 1997

Unigraphics

Unigraphics (abbreviated UG) is a high-end CAD/CAM system, available for student use at USC, courtesy of EDS/Unigraphics, which has a long-standing history of collaboration with the Programmable Automation Lab.

The system is powerful, but it also is large and complex. The following notes are meant as a roadmap to facilitate learning the rudiments of the system, so as to be able to model objects in it, and to create files for "solid printing" via rapid prototyping machines.

Starting Up

UG runs in any of USC's color SPARC workstations with 32 MB of memory under Solaris 2.x, and also in the 'aludra' server. It is recommended that you run in a workstation, because the system takes over 80MB of memory when running in the server, and often gets killed because it exceeds the preset process memory limits.

To be able to use UG add to your .login file:

if (-e /usr/usc/ugii/default/setup.csh) then

source /usr/usc/ugii/default/setup.csh

endif

To start UG type

ugii

Reading the Documentation

The main window and the graphics window come up. The main window covers the whole screen. It is best to make this window fairly small, and also to reduce the graphics window. Click help on the title bar and then select Documentation. A separate window using the Worldview documentation package appears.

Select CAD, and then Unigraphics Essentials. Read the introduction and ignore the "user exits" section and applications other than gateway and modeling. Read the introduction to each of the chapters to see what is in them. Ignore the appendices. The most relevant chapters are 6, on how to control the display (the "rotate" command is especially useful), 7 on work coordinate systems, and portions of 14, on how to define points, lines, and so on.

In the Modeling manual, again read the introduction and the chapter introductions. The most useful sections are on creating features, feature operations, sketching and editing.

Using the System

To get started try to do something similar to the classroom demonstration. Note that placing the mouse over any button produces a short description of the button's effect. First, from the file menu open a new file and give it some name of your choice, finishing in .prt. Note that on the top left corner of the graphics window there is a "traffic light". When this light is green the system is ready for input; when it's red, the system is computing. The graphics window shows the working coordinate system XC, YC, WC in orthographic projection along the ZC axis.

From Applications select Modeling. Then, from Toolbox select Sketch. Use the Point Subfunction to create a polygon by clicking on the cursor option and then on the endpoint option to close the polygon. Then dimension the sketch using horizontal and vertical dimensions. The system will not extrude an incompletely dimensioned sketch. Assigning dimensions essentially parameterizes the sketch and lets us later modify it by changing just the numeric values of the dimensions.

Ignore the requests for names, and use mouse picks to identify the entities you need. Normally the system puts you back in the operation you just executed, in case you want to do another of the same kind. This implies that sometimes you have to Cancel to get out and into another operation. There are also occasions in which more OKs are needed than you would expect.

Now select Features from the Toolbox,and pick the first option, extruded object. Take the defaults and get a solid slab from your sketched polygon. To see it is 3-D, go to View in the top menu bar, select Rotate, and then drag the mouse in the graphics window to change the viewpoint. The graphic window's scroll bars serve to translate the image horizontally and vertically, and to zoom.

Define other features and add and subtract them from the extruded object. To edit, pick Edit from the top menu bar.

Solid Printing

This should be easy, by selecting a rapid prototyping option in the export category. But we don't yet have a license to use it, so I haven't tried it yet.

Hard Copy Display

There may be a way of generating a PostScript file from the graphics window from within UG, but I haven't found it. A convenient procedure involves capturing the screen with Unix utilities. From a Shell or Xterm window run xv. A main window appears. Click the right mouse button on it and the control window for xv appears. Select Grab. This brings up another window. Set the delay time to 5 or 10 seconds, click Autograb, and quickly place the cursor on the window you want to capture. You'll hear bells denoting the beginning and end of the capture. Back in the control window click Print. This pops the print window, in which you just have to do OK, unless you want a print command other than lpr.

Comments

Send me e-mail with suggestions on what you think is needed in this document. My goal is to provide something that gets you started, and is short. To do more sophisticated operations one has to read the documentation and try things out. The first contact with the system and the documentation can be a bit of a shock. Here I am just trying to help overcome it.