Copyright Goodheart-Willcox Co., Inc. Chapter 4 Understanding Three-Dimensional Coordinates and User Coordinate Systems 101 X and Y axes are not aligned with the quadrants of the circle, as indicated by the grip locations. This may not be what you expected. The X axis orientation is determined by the pick point on the circle. Notice how the X axis is pointing at the pick point. To rotate the UCS in the current plane so the X and Y axes of the UCS are aligned with the quadrants of the circle, use the ZAxis option of the UCS command. Select the center of the circle as the origin and then enter the absolute coordinate 0,0,1. This uses the current Z axis location, which also forces the X and Y axes to align with the object. Refer to Figure 4-27C. This method may not work with all objects. Setting the UCS to the Face of a 3D Solid The Face option of the UCS command allows you to orient the UCS to any face on a 3D solid, surface, or mesh object. The Face option is available in the UCS icon shortcut menu. Select the option and then pick a face on the model. After you have selected a face, you have the options of moving the UCS to the adjacent face or fl ipping the UCS 180° on the X axis, Y axis, or both axes. Use the Next, Xflip, or Yflip option to move or rotate the UCS as needed. Once you achieve the UCS orientation you want, UCS Ribbon Home Coordinates Visualize Coordinates Face Type UCS B A Point on positive Z axis Origin Cylinder is subtracted Figure 4-26. A—Using the ZAxis option to establish a new UCS. B—The new UCS is used to create a cylinder, which is then subtracted from the base to create a hole. Pick point A B C Figure 4-27. A—This circle is rotated off of the WCS XY plane by an unknown number of degrees. It will be used to establish a new UCS. B—The circle is on the XY plane of the new UCS. However, the X and Y axes do not align with the circle’s quadrants. C—The ZAxis option of the UCS command is used to align the UCS with the quadrants of the circle.