CAD Design Overview

The CAD design tools are by far the more powerful tools for creating complex and original designs (see: CAD Designs Library Examples ). They are also just as useful for creating simple and standard designs but require more CAD design skills than the parametric system. Having said this the CAD design tools in Sheet Lightning have been created to make the 3D CAD design as simple as possible. A few fundamentals need to be appreciated to make the best of these tools.

On opening a CAD design child window the view is in object selection mode . This means the mouse cursor can be used to select and highlight the individual objects in the view (see: Selected Objects ). Many commands require either a single or multiple selection to be made for the command to be available (i.e. enabled, shown grayed if disabled). In object selection mode the nearest object to the cursor on a left click is highlighted (the object must be within a proximity margin of the selection), or if already selected the object is unselected. Object selection mode therefore toggles the object's selection. The edit menu offers a number of commands for easy selection (e.g. Select All, Unselect All, Select Linked etc). The view always gravitates back to object selection mode as other commands complete. The current object selection affects the enabling/disabling (by greying) of many of the commands. Some commands are available when only a single part is selected (e.g. the Edit Part command). Others commands require more than, or at least one object to be selected to be enabled. The grey state of all taskbar icons and menu items is updated each time the current selection set changes.

Understanding the use of color in the CAD design view is important because the color defines the selected state of an object (in object selection mode) or may indicate a prompt for user selection of an object in the view. The following outlines the general color code:

1. Main objects are colored red when unselected and white when selected.
2. Construction lines are grey when unselected and white when selected.
3. Green indicates the current command demands a selection from the green highlighted entities. This is effectively a request to the user to select an entity such as a node or center line, or perhaps a complete part. The prompt is also indicated by the text in the status bar at the base of the screen.
4. Cyan (light blue) is a special highlight to show a command is in progress on the object. No user selection is required, but the highlight is simply used as an indicator of the target object.
5. Dimensions have their own coloring system. They are cyan (light blue) for unselected and yellow for selected.

Dialog controls appear and disappear on the command dialog panel as the commands are executed on a view. At any time during a the execution of a command the ESCAPE key can be used to abort the command and return the view to object selection mode .

The command dialog showing on the command dialog panel relates to the active design view. If other design windows are activated the command dialog is switched current command dialog in the active view.

The main cursor is usually an arrow. During 3D point selection commands a second 'cross cursor' also appears. This cross cursor defines the current position of in the 3D space. It is usually accompanied by the cursor box showing the position of the 3D cursor relative to the origin. The 3D cursor normally moves in unison with the mouse arrow cursor, until the 3D movement becomes restricted in some way (e.g. sliding along a center line). The 3D cross cursor then moves in a restricted manner is response to the main arrow cursor movement so the screen position of the two cursors may differ.

The cursor box indicates the plane in which the the cursor is moving in the 3D view during point selection. The cursor plane can be altered using the right click menu. When a cursor plane is active one axis value is static. The point selection command dialog has an edit box to allow this static value to be altered.

When snap tools are used during point selection the 3D cursor changes slightly to show a small box at the center of the cross. During snap operations the possible snap entities should also be highlighted in green on the view.