CAD Edit CPL

CAD Edit > CPL – Construction Plane

The construction plane is referred to as the CPL. It is a selectable and user definable 3D co-ordinate system that allows the location of the X-Y plane to be continually repositioned for easier and more efficient model

construction. In effect, the value of Z (unless otherwise specified) is always equal to zero, thus enabling the user to approach model construction such that the values of X and Y only, are the current significant components. If enabled, the current CPL is represented in the graphics display area by a symbol that

shows its X and Y axis positive directions. The symbol remains a constant size, relative to the screen, for all Zoom and View manipulations (except for some perspective view definitions).

The standard construction planes provided are Top, Bottom, Front, Back, Left, Right and Isometric. All of these standard CPLs originate about the absolute system coordinates X=0, Y=0 and Z=0. A new CPL can be defined by specifying three co-ordinate locations, manipulating existing CPLs by rotation and/or translation and alignment to user-defined views.

The selection of a suitable CPL, in conjunction with the appropriate View and Zoom selections, enables model construction to be achieved more easily and efficiently. In effect, the construction is performed by engaging a two dimensional approach to a three dimensional object, thus simplifying many of the procedures involved in complex 3D model creation. Although selection of a CPL will provide an active co-ordinate system, the model exists in an absolute model co-ordinate system which cannot be changed. The List Verify command will always display both the current CPL co-ordinates and the model co-ordinates of a selected entity.

Each CPL can display a grid with a user-specified spacing. The grid is a two dimensional array of uniformly spaced points that act as a visual and locating aid to model construction. The grid displays on the X-Y plane of the CPL originating at the CPL co-ordinates X=0, Y=0, Z=0.

Cpl Select

The Cpl Select command allows the selection of a CPL for current model construction. When selected, the Select CPL dialog box is enabled listing all standard and user-created CPLs for the current model. The standard CPLs are Top, Bottom, Front, Back, Left, Right and Isometric. A user-defined CPL is created with the CPL New command.

The CPL selected is immediately activated, with the parameters determined during previous use (i.e. subject to any user manipulations). Only one CPL is selected at any one time, irrespective of the number of views currently displayed.

Cpl Reset

The Cpl Reset command allows the previously determined Cpl Set parameters of the current CPL to be restored. A CPL can undergo various user manipulations (e.g. translations, rotations and view alignment) with the Cpl Change command. If these manipulations are unsuitable, or no longer required, the Cpl Reset command will restore the CPL to the last CPL parameters set when the Cpl Set command was last performed.

Cpl Set

The Cpl Set command allows the current CPL location, orientation and grid parameters to be saved for the current CPL. These saved CPL parameters will be restored whenever the Cpl Reset command is performed for that selected CPL. These parameters are filed with the model.

Cpl Reset-Std

The Cpl Reset-Std command allows the parameters of the current CPL to be reset with those of a standard CPL. When selected, the Std Cpl (standard CPL) sub-menu is enabled listing only the standard

CPLs for the current model. The standard CPLs are Top, Bottom, Front, Back, Left, Right and Isometric.

A CPL can undergo various user manipulations (e.g. translations, rotations and view alignment) with the Cpl Change command. If these manipulations are unsuitable, or no longer required, the Cpl Reset-Std command will restore the CPL to the standard CPL parameters of the selected standard CPL.

Cpl Change

The Cpl Change command enables the Cpl Change sub-menu which allows the current CPL to be changed. The CPL can be changed by translation, location of a new origin, rotation, redefinition of co-ordinate point locations and alignment to a selected view.

Translate

Allows the current CPL to be relocated. Two point locations are selected to define the distance and direction of the translation.

Origin

Allows the current CPL origin to be relocated. A single point location is selected which defines the new CPL origin. The orientation of the CPL is unchanged.

Rotate

Allows the current CPL to be rotated by a specified angle and about a defined axis. Two point locations are selected to define the start and end of the axis of rotation respectively (and subsequently the direction of the axis). The angle of rotation is then specified. The direction of rotation is determined using the ‘right-hand rule’. With the right hand half closed and the thumb extended at right angles, the thumb points in the direction of the axis and the curled fingers indicate the positive direction of rotation.

3-Points

Allows the current CPL to be redefined in respect to both location and orientation by selecting three point locations. The first point location selected defines the new location of the CPL origin. The second point location selected defines the positive direction of the X-axis and the orientation of the CPL relative to the origin. The third point location defines the positive direction of the Y-axis of the CPL relative to the origin.

View

Allows the current CPL to be aligned to the current view definition.

Cpl Show

The Cpl Show command allows the symbol representing the current CPL to be visually restored to the graphics display area. The selected CPL parameters remain unaffected.

Cpl Hide

The Cpl Hide command allows the symbol representing the current CPL to be visually removed from the graphics display area. However, the selected CPL parameters remain active.

Cpl Set-Grid

(From Right Menu Only)
The Cpl Set-Grid command enables the CPL Set-Grid Defaults dialog box which allows the grid parameters for the current CPL to be determined.

X Grid spacing Allows the X grid value to be defined.
Y Grid spacing Allows the Y grid value to be defined.
X Reference spacing Allows the X reference spacing to be defined.
Y Reference spacing Allows the Y reference spacing to be defined.

The grid is a two dimensional array of uniformly spaced points that act as a visual and locating aid to model construction. The grid displays on the X-Y plane of the CPL and originates at the CPL co-ordinates X=0, Y=0, Z=0. When enabled with the Cpl Grid-On command, the grid points are displayed. The parameters that are specified are the X and Y grid spacings, in model units, and the X and Y reference spacings.

The reference spacings are a factor indicating the number of grid spacings between the reference points of the grid. The X and Y values for each of the two parameters need not be equal. The grid spacings are displayed by dots while the reference spacings are displayed as small crosses.

Cpl Rad-Grid

(From Right Menu Only)

The Cpl Rad-Grid command is used to set the radial grid. The grid displays on the X-Y plane of the CPL and originates at the CPL co-ordinates X=0, Y=0, Z=0. When Cpl Grid-On command is selected, the grid points will be displayed as dots and the reference points as small crosses. All the points are on a number of radial axes. The number of axes is specified by the parameter Number of Sectors.

The distance between two adjacent grid points on the same axis is specified by the Radial Grid Spacing parameter. Reference points are special grid points appearing on reference axes between a given number of radial grid points. The reference axes are specified by the Angular Reference Spacing parameter. For example, if this parameter is set to three (3), then every third axis is a reference axis. The first reference axis is the CPL X-axis. The axes are counted anti-clockwise.

The number of grid points between two reference points on the same axis is specified by the Radial Reference Spacing parameter. For example, if this parameter is set to five (5), then every fifth grid point on a reference axis is a reference point. The first reference point is the CPL origin. When Cpl Snap-On is selected, all location selections will snap to the nearest grid points.

The grid information is filed with the model rather than stored in the values.def file when the File Defaults Write command is executed. When Mapping Tool is available and Mapping Grid is set to On, then the radial grid will not be displayed even if it is currently set.

When the Cpl command is selected, the CPL Rad-Grid Defaults dialog is displayed.

Radial grid spacing Defines the radial grid spacing and is set in model units along each radial axis.
Number of sectors Allows the number of sectors of the grid to be defined.
Radial reference spacing Allows the reference radial spacing of the grid to be defined.
Angular reference spacing Allows the reference angle spacing of the grid to be defined.

The system will ignore zero and negative numbers and use the original (default) value displayed in the dialog box. If a real number is provided where an integer is required, then it will be converted to the nearest integer.

The number of sectors should be greater than the angular reference spacing and preferably, a multiple of the angular reference spacing so that the reference points appear evenly. If the number of sectors is less than the angular reference spacing, then there will only be on reference axis (the CPL axis). Only one kind of grid (radial or X-Y) can be activated at a time. Selecting Radial Grid will automatically turn off the X-Y grid and vice versa.

CPL Grid-On

The Cpl Grid-On command allows the grid specified for the current CPL to be enabled and displayed.

The grid is a two dimensional array of uniformly spaced points that act as a visual and locating aid to model construction. The grid displays on the X-Y plane of the CPL, originating at the CPL co-ordinates X=0, Y=0, Z=0. If the current zoom scale is too large, in relation to the specified grid spacing, the grid will not be displayed but will be enabled.

Cpl Grid-Off

The Cpl Grid-Off command allows the grid specified for the current CPL to be disabled and removed from the screen.

Cpl Snap-On

The Cpl Snap-On command allows the snapping of points to the closest grid point to be activated. With a grid activated, all location selections will snap to the nearest grid point.

Cpl Snap-Off

The Cpl Snap-Off command allows the snapping of points to the closest grid point to be deactivated. All location selections will be true locations and will not snap to the active grid.