Lines in Shape Maker are the basic tool for creating a model wireframe. Lines in many respects determine the shape of the modeled surface and are reference for surface patches. It is important to clarify that surfaces can only be defined on topologically connected lines. Shape Maker uses three main types of lines: spatial lines, lines on the surface, and lines of intersection of surfaces. Spatial lines and surface lines can be edited. The lines of intersection of the surface depend on the shape of the intersected surfaces and editing these lines is not possible.
Defining spatial lines.
There are several ways to define lines. We will consider only the most commonly used. You can start draw lines using the following command:
Or by clicking the button from the Create toolbar:
The spatial lines are defined by the start and end points. A straight line is drawn between the points. The coordinates of points can be set both with the cursor in the working window and with the use of object and topological links. If necessary, the exact coordinate values can be set by the keyboard. After selecting a command, the following message appears in the coordinate input line and the coordinates of the current point are displayed:
If you need to enter other coordinates, just click the cursor in the coordinate input field or the left or right arrow on the keyboard and edit the line with the coordinates. After entering the first point of the line, the system remembers the coordinates of the entered point as the coordinates of the current point and issues a message to enter the next point. At the same time, a rubber line appears on the screen from the first entered point to the cursor location point. After entering the second point, a straight line appears on the screen.
Lines are drawn by the current color and saved to the current block. Entered points are also saved to the current block. After entering the second point and the line appears on the screen, you can continue to enter the next point. A 2nd line will appear having a common point with the first line.
Moreover, the inserted lines are topologically connected to each other through a common point. That is, when the position of the common point changes, both lines shape will be changed. If you do not need to enter a chain of interconnected lines, you can press Esc or the right mouse button and start entering the first point of a new line. In the process of entering new lines, you can change the projection, work plane, and also the working volume.
Defining surface lines.
Lines on the surface differ from spatial lines in that the shape of the line is defined as the intersection of the master projection of the line with the surface on which the line lies. You can start entering lines on the surface with the same command, with one difference - the surface line input mode must be enabled.
Or by clicking the button from the Create toolbar:
The system uses the concept of a current surface to enter surface lines. When you enter the first surface line from the start of the session, the current surface is undefined, so the following message is displayed in the coordinate input window:
You can specify the current surface for entering surface lines by clicking on this surface in the working window or enter the name of this surface in the coordinate input window.
The contour of the selected surface will be highlighted in red. When you enter all subsequent surface lines per session, the outline of the current surface will always be highlighted in red. Entering surface lines is carried out as well as spatial lines, but with some limitations: - The surface lines must be entirely inside the surface boundaries or be topologically connected by boundary points with the surface boundaries. - The surface area on which the surface lines are set must be uniquely defined on this projection. - The line must not cross the surface contour.
If you enter one of the points outside the surface contour, the following message is displayed.
If for any of the above reasons it is not possible to build a line, a message is issued.
As a result of successful construction of the line, on the projection from which the line was set, this line will look straight. When switching to another projection, it is seen that these lines are projected onto the surface.
If during the input of surface lines it became necessary to change the current surface, this can be done with the following command.
Or from the Settings toolbar:
In this case, the question appears in the coordinate input line:
You can specify a new work surface without interrupting the input of surface lines. A surface line cannot be placed simultaneously on several surfaces. On each such surface the lines must be places separately. When entering a surface line, only boundary lines and corner points of the current surface and lines and points lying on this surface can be used as topological snap objects.