About Selecting References for Screws
Use the Select References dialog box to define all placement references needed for the screw fastener. Two arrows indicate the position and the orientation of the screw fastener.
1. Click Tools > Intelligent Fastener > Screw and then click one of the following:
Assemble on reference
Assemble by mouse click
The Select References dialog box open and the Position Reference collector is activated.
2. Select the reference as is described below:
If you clicked Assemble on reference, select the position point, axis, or cylindrical surface.
If you clicked Assemble by mouse click, select the first and second dimension reference.
The Placement SurfaceScrew head collector is activated.
3. Under Placement Surfaces, you can select references for the following:
The Screw head placement surface.
The Nut or thread placement surface.
* 
If the Screw head surface has same orientation as the Nut or thread surface, a screw fastener with a thread is created. If the surface orientation is opposite, a screw fastener with a nut is created.
—Indicates that a nonsolid surface is selected. If Creo Intelligent Fastener cannot find a solid surface at the same location, the hole is not created. Best practice is to select a solid surface.
—Indicates that the part cannot be changed.
Click in the Orientation collector to select an additional surface to define the orientation of the screw fastener:
Select Align first side to align the screw head side to the orientation surface.
Select Align second side to align the nut or thread side to the orientation surface.
* 
Aligning screw fasteners is available only in the full version.
4. Click OK to finish the selection of the screw reference. The Screw Fastener Definition dialog box opens.
5. Click Cancel to close the Select References dialog box.