Selecting Edit Points
On entering an entity's edit mode, the control points of a curve will be marked by small circles. Control points are manipulated by dragging the mouse when they are selected. Points are selected using exactly the same approach as the selection of entities. Individual points can be selected by Left-Clicking on the points, (Figure 1). If no point for selection is found, region mode will be automatically entered, (Figure 2). Additional points can be added to the selection set by pressing the Ctrl key. Region selection mode can be entered directly by pressing the Shift key. Both the Ctrl and Shift can be used together interchangeably. Points are also selected when the user selects cells of the coordinate grid in the Entity Attribute Panel.
Once a point or set of points has been selected, with the Left-Click button still down the points can be either manipulated using the Enhanced 3D Editing mode or in the plane of the current screen view with 3D Mode off. Pressing the control key will constrain the movement of the point to the closest axis direction, (Figure 3). Points can also be manipulated using the arrow keys with 3D Editing on or off. When 3D Editing is off points will move in the screen plane. The distance moved by each press of the key is defined by the Key Nudge parameter in the PolyCAD Options Panel -> Manipulation Options.
Points can be interactively added to the curve definition by pressing the A key. The location within the curve will be displayed on screen, (Figure 4). Not all curves will support the interactive adding of points depending on the definition, check the status bar information for current options.
Selected Points can be deleted by pressing the Del key. It is not possible to delete more points than are required for a minimum definition of the entity. For example, a Polyline requires two points a cubic B-Spline requires four points.
Editing Curve Control Points Numerically
The individual coordinate components of each control point can be edited numerically from the grid in the Entity Attribute Panel. When a point is selected in the coordinate grid it is show highlighted in the model view. In addition, to editing individual coordinates, points can be added, removed, copied using the following tool buttons above the grid.
|Inserts a point in the line segment between the currently selected row and the one above. The point is located on the midpoint of the line segment. If the first row is selected, the new point is positioned using the opposite vector between the first and second points of the curve.|
|Inserted a point in the line segment between the currently selected row and the one below. The point is located on the midpoint of the line segment. If the last row is selected, the new point is positioned using the opposite vector between the last and second last points of the curve.|
|Opens the Fill Values dialog box which set the selected coordinate component of all the control points to the same value.|
|Removes (deletes) the currently selected rows (control points).|
|Copies the control point coordinates values to the windows
for pasting into a spreadsheet for example.