Chapter 4: Using Working Planes
Go to the Next Chapter
Go to the Previous Chapter
Go to the Table of Contents for This Manual
Go to the Guides Master Index
Chapter 1 *
Chapter 2 *
Chapter 3 *
Chapter 4 *
Chapter 5 *
Chapter 6 *
Chapter 7 *
Chapter 8 *
Chapter 9 *
Chapter 10 *
Chapter 11 *
Chapter 12 *
Chapter 13 *
Chapter 14
4.1 What Is a Working Plane?
Although your cursor appears as a point on your screen, it actually represents a
line through space, normal to the screen. In order to be able to pick a point with
your cursor, you first need to define an imaginary plane that, when intersected by
the normal line of your cursor, will yield a unique point in space. This imaginary
plane is called a working plane. Another way to think of the interaction between
your cursor and your working plane is to picture your cursor as a point that moves
around on your working plane. The working plane, then, acts as a "tablet" on
which you write with your cursor. (The working plane need not be parallel to your
display screen.)
Figure 4-1 Relationships among display screen, cursor, working plane,
and picked point
A working plane is an infinite plane with an origin, a 2-D coordinate system, a
snap increment (discussed below), and a display grid. You can define only one
working plane at a time. (Creating a new working plane eliminates your existing
working plane.) The working plane is separate from the coordinate systems; for
example, the working plane can have a different point of origin and rotation than
the active coordinate system. See Section 4.3.5, "Working Plane Tracking," for a
discussion of how to force the active coordinate system to track the working plane.
4.2 Creating a Working Plane
By default, when you initiate your ANSYS session, there is a working plane
located on the global Cartesian X-Y plane, with its x and y axes colinear with the
global Cartesian X and Y axes.
4.2.1 Defining a New Working Plane
You can define a new working plane by using any of these methods:
- To define a working plane by three points, or by locating it on the plane
normal to a viewing vector at a specified point, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Align WP with>XYZ Locations
- To define a working plane by three nodes, or by locating it on the plane
normal to a viewing vector at a specified node, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Align WP with>Nodes
- To define a working plane by three keypoints, or by locating it on the plane
normal to a viewing vector at a specified keypoint, use one of these
methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Align WP with>Keypoints
- To define a working plane by locating it on the plane normal to a viewing
vector at a specified point on a line, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Align WP with>Plane Normal to Line
- To define a working plane by locating it on the X-Y (or R-
) plane of an
existing coordinate system, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Align WP with>Active Coord Sys
Utility Menu>WorkPlane>Align WP with>Global Cartesian
Utility Menu>WorkPlane>Align WP with>Specified Coord Sys
4.2.2 Controlling the Display and Style of the Working Plane
To obtain the current status (that is, the location, orientation, and enhancements)
of the working plane, use one of these methods:
Command(s):
GUI:
Utility Menu>List>Status>Working Plane
To reset the working plane to its default location and style, use the command WPSTYL,DEFA.
4.2.3 Moving the Working Plane
You can move a working plane to a new location (that is, a new origin) using any
of the following methods (all of which translate the working plane to a new location
parallel to its original location):
- To move the working plane origin to the average location of keypoints, use
one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Offset WP to>Keypoints
- To move the working plane origin to the average location of nodes, use one
of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Offset WP to>Nodes
- To move the working plane origin to the average of specified points, use
one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Offset WP to>Global Origin
Utility Menu>WorkPlane>Offset WP to>Origin of Active CS
Utility Menu>WorkPlane>Offset WP to>XYZ Locations
- To offset the working plane, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Offset WP by Increments
4.2.4 Rotating the Working Plane
You can rotate your working plane to a new orientation in two ways: by rotating
the working plane's x-y coordinate system within the plane, or by rotating the
entire plane to a new position. (If you do not know the rotation angles explicitly,
you might find it easier to simply define a new working plane at the correct
orientation using one of the methods described above.) To rotate the working
plane, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Offset WP by Increments
4.2.5 Recreating a Previously-defined Working Plane
Although you cannot actually "save" a working plane, you can create a local
coordinate system at the working plane origin, and then use this local coordinate
system to recreate a previously-defined working plane.
- To create a local coordinate system at the working plane origin, use one of
these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Local Coordinate Systems>Create Local CS>
At WP Origin
- To use the local coordinate system to recreate a previously-defined
working plane, use one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Align WP with>Active Coord Sys
Utility Menu>WorkPlane>Align WP with>Global Cartesian
Utility Menu>WorkPlane>Align WP with>Specified Coord Sys
4.3 Working Plane Enhancements
Using the WPSTYL command or GUI
path described earlier, you can enhance your working plane with a snap
increment, a display grid, retrieval tolerance, and coordinate type. Then, you can
force your coordinate system to follow your working plane as the working plane is
moved using one of these methods:
Command(s):
GUI:
Utility Menu>WorkPlane>Change Active CS to>Global Cartesian
Utility Menu>WorkPlane>Change Active CS to>Global Cylindrical
Utility Menu>WorkPlane>Change Active CS to>Global Spherical
Utility Menu>WorkPlane>Change Active CS to>
Specified Coordinate Sys
Utility Menu>WorkPlane>Change Active CS to>Working Plane
Utility Menu>WorkPlane>Offset WP to>Global Origin
4.3.1 Snap Increment
It is difficult, if not impossible, to position your cursor at a precisely defined spot on
the working plane. In order to pick with precision, you can use the WPSTYL command or GUI path to establish
a snap increment. Once a snap increment is defined, any point that you create by
picking will be located at the nearest snap point in your working plane. Stated
mathematically, when your cursor falls within the range
N*SNAP - SNAP/2 <= x < N*SNAP + SNAP/2
for any integer N, the x coordinate picked is assigned the value
xp = N*SNAP.
(The same snap increment is used for both x and y coordinates, where x and y
are in terms of the working plane coordinate system.) You can visualize the snap
increment as creating a pattern of square boxes, as shown below. Any locational
pick you make will "snap" to the center of its box.
Figure 4-2 Snap increment
4.3.2 Display Grid
You can create a square display grid to help you visualize the location and
orientation of your working plane. The grid spacing, style, and boundaries are
established with the WPSTYL command.
(This grid is not related in any way to your snap points.) By issuing WPSTYL without arguments, you can toggle
the display of the grid on and off.
4.3.3 Retrieval Tolerance
An existing entity that you want to pick might lie close to, but not exactly on, your
working plane. By specifying a retrieval tolerance with the WPSTYL command or GUI path, you can
instruct the program to consider entities that are within that tolerance to be on the
working plane. This tolerance, in effect, gives "thickness" to your working plane,
for retrieval picking purposes.
4.3.4 Coordinate Type
There are two types of working planes that you can choose from: Cartesian and
polar. Discussion up to this point has concentrated on Cartesian working planes
but polar working planes may be used if your geometry is easily described in polar
(radius, theta) coordinates. Figure 4-3 shows a polar working plane grid that was
activated with the WPSTYL command.
Picking with a polar working plane works the same way as picking on a Cartesian
working plane. Grid point locations for the snap feature are located by specifying
the radial distance between snap points (SNAP on WPSTYL) and the angle between snap
points (SNAPANG).
Figure 4-3 Polar working plane grid
4.3.5 Working Plane Tracking
If you've used working planes in conjunction with coordinate systems to define
your geometry, you've probably discovered that working planes are completely
separate from coordinate systems. When you change or move the working plane,
for instance, the coordinate system does not change to reflect the new working
plane type or location. This can be frustrating if you are using a combination of
picking (based on the working plane), and keyboard input of entities such as
keypoints (based on active coordinate system). For instance, if you move the
working plane from its default position, then wish to define a keypoint at the new
origin of the working plane with keyboard input (that is K,1205,0,0,0), you'll find that the keypoint is located
at the coordinate system origin rather than the working plane origin (see Figure
4-4).
Figure 4-4 Working plane/coordinate system mismatch
If you find yourself forcing the active coordinate system to follow the working plane
around as you model, consider using an option on the CSYS command or GUI path to do this
automatically. The command CSYS,WP or
CSYS,4 will force the active coordinate
system to be of the same system type (for example, Cartesian) and in the same
location as the working plane. Then, as long as you leave the active coordinate
system be WP or 4, as you move the working plane, the coordinate system will
move with it. The coordinate system is also updated if you change the type of
working plane that you are using. For instance, if you change the working plane
from Cartesian to polar, the active coordinate system will change from Cartesian
to cylindrical.
To revisit the example discussed above, suppose that you wish to place a
keypoint at the origin of your working plane after you've moved that plane. You
moved your plane, as before, but this time you activated working plane tracking
(CSYS,WP) before you moved the plane.
Now, when you use the keyboard to locate your keypoint (that is K,1205,0,0,0), the keypoint is placed at the origin of
the working plane because the coordinate system is in the same location as the
working plane (see Figure 4-5).
Figure 4-5 Matched working plane/coordinate system (CSYS,WP)
Go to the beginning of this chapter