 To automatically dimension 
 the part using datum dimensions, use the Auto Dimensioning 
 option. The system places the datum at the lower left corner and then 
 dimensions the remaining points. Select the option and move the cursor 
 into the work area to open the dialog shown here. Click Yes 
 to proceed or No to cancel. Cancel 
 any auto-dimensioning in progress by pressing <Esc>.
 To automatically dimension 
 the part using datum dimensions, use the Auto Dimensioning 
 option. The system places the datum at the lower left corner and then 
 dimensions the remaining points. Select the option and move the cursor 
 into the work area to open the dialog shown here. Click Yes 
 to proceed or No to cancel. Cancel 
 any auto-dimensioning in progress by pressing <Esc>.

Note: To place the datum somewhere other than the lower left corner of the part, use the Datum Origin option to define the origin before using auto-dimensioning.