3D Drawing with AutoCAD - Section 8

34.1 SCP 3D

As already explained, the Personal Coordinate System is used to locate the Cartesian plane at any point in our drawing and to modify the direction of the axes, X, Y and Z. The Coordinate System icon will reflect the new origin and direction of the axes if the option “UCS icon parameters-Show UCS icon at origin” in the context menu is active. Those same options can be set using the dialog box in the Coordinates section of the View tab.

Let's look now at the various methods we can use to establish new SCPs.

Origin 34.1.1

The simplest modification of the Universal Coordinate System to a Personal Coordinate System is to modify the point of origin. The orientation of the X, Y and Z axes are unchanged. Therefore, everything is as simple as using the Origin button in the Coordinates section of the View tab and pointing to the new point with the mouse.

34.1.2 Face

The “Face” button creates a UCS where the plane formed by the X and Y axes are aligned to the face of an object and the point of origin is located on said plane. If the orientation of the axes does not match what you want, the command line window offers the option to rotate them on the X and/or Y axis.

34.1.3 Three points

If we use the “3 points” option, we must indicate the coordinates of the new origin, then a point that will define the positive direction of X and then another on the XY plane that allows us to establish the positive direction of Y. Since Y will always be perpendicular to X , this third point does not necessarily need to be on the Y axis. Finally, the positive direction of Z is obvious once the previous ones are established.

34.1.4 Vector Z

This is the alternative option to the previous one. If we establish a point of origin - such as 3 points - and then with another point the positive direction of the Z axis, the positive direction of the XY plane is bound to the SCP icon.