Use the Associative by Entity/Position function to define a plane by a selected entity and an indicated position. Note that the resulting plane will be associative to the entity and position that you indicate. It will be important to understand this relationship before attempting to modify the entity and/or position.

Using the Function:

1. Select Assoc. Entity/Position from the Create>Plane submenu.

2. Select the entity.

3. Indicate a plane origin using the Position Menu. The plane is then created based on the entity and position that you had indicated.