|CAD System Web Site - Computer Aided Design Software|
|by Makoto Honda|
6. Current Plane
The concept of the current plane is very important in a 3D CAD system. The current plane provides “a frame of reference” in the user’s mind. The current plane is also a logical mechanism to map the cursor position (on the 2D screen or viewport surface) into the 3D coordinate in the 3D space. That is, the current plane provide a bridge between a 2D cursor and the corresponding point in 3D space. When the user clicks the viewport with the intent of specifying a 3D location (this user action is referred to as Indicate), the user is really clicking a point on the current plane. The actual 3D coordinate perceived by the system, of course, depends on where the current plane is located and how it is oriented at the time of the click.
The current plane is sometimes referred to as “construction plane” for a good reason. In this CAD system also, the current plane is often used during the construction as well as manipulation of the geometric elements. For instance, most of the 2D elements (flat elements) are created on the current plane. The mirror operation (see transformation) uses the current plane as the mirror plane.
The Grid Snap mode allows the snapping of grid intersections of the current plane, allowing a quick construction of the geometry.
Recognizing the importance of the current plane, this CAD system provides various functions to allow for the easy and intuitive manipulations of the current plane: In addition to some preset orientations, the origin as well as orientation can be manipulated. The current plane property dialog box allows various attribute settings including grid intervals and display characteristics.
Preset Current Plane (XY / YZ / XZ)
Snap On Element
Copyright © 2010-2013 Makoto Honda. All Rights Reserved. www.iNET1000.com