I'm sure many of you are familiar with using the reference option of the rotate command, but here's something you might have missed.
Our mission is to rotate OBJ. Z (the red polyline) around point A so that line BC is parallel with line DE (the yellow polyline).
- Execute the rotate command.
- At the prompt (Select objects:), select the red polyline that represents OBJ. Z, then press enter to accept.
- At the prompt (Specify base point:), select the endpoint at point A.
- Type R and press enter to accept. (R is used to access the "Reference" option of the rotate command.)
- At the prompt (Specify the reference angle <##>:), select the endpoint at point B then the endpoint at point C.
- At the prompt (Specify the new angle or [Points] <##>:), Type P and press enter. (P is used to access the "Points" option of the rotate command. This option allows us to select the new bearing for line BC by selecting two points.)
- Select the endpoint at point D, followed by the endpoint at point E.
This process could be used in many situations such as rotating a land survey based on assumed coordinates. The whole survey would be "OBJ> Z" and the basis of bearings would be line DE.
The scale command has the same Reference and Points options. Be sure and look for options on other commands. You'll find them in brackets.
Another thing of which to be cautious is using objects with elevation. In the case of rotate, the z value would have no effect, but having different z values when scaling might give you unwanted results.