To Place a UDF Where the Only Reference Is a Coordinate System
When placing a UDF with a coordinate system as the only external reference you have a number of choices:
• Select an existing coordinate system.
• Asynchronously create a coordinate system using the regular workflow for asynchronous datum creation.
• Click > and create an on-surface coordinate system.
Follow this procedure to place the UDF through an on-surface coordinate system where the only reference is a coordinate system.
1. Create a UDF with a coordinate system as the only external reference.
2. With a target model open, click > 
User-Defined Feature. The Open dialog box opens.
User-Defined Feature. The Open dialog box opens.3. Select the created UDF group file and click Open. The Insert User-Defined Feature dialog box opens.
4. Select Create on-surface coordinate system within UDF (dynamic preview available) option and click OK. The User Defined Feature Placement dialog opens to the Placement tab and the UDF preview appears.
5. Define the Placement references:
a. Select ON SURFACE CSYS in the References of Original Features list. The layout on the right side of the Placement tab changes to a layout similar to the Coordinate System dialog box. Select a plane or a surface to place the coordinate system reference in the Reference Surface box. A preview image of the UDF with coordinate system dragger handles appears on the model.
b. Specify the offset references in the References box and use the dragger handles to position the UDF. The coordinate system offset type can be Linear, Radial, or Diameter.
c. If necessary, modify the axis of the coordinate system location. The second axis direction sets the normal direction. Leave the first axis direction in the same direction as the placement surface.
6. Click 
. All UDF features regenerate successfully and the User Defined Feature Placement dialog closes.
. All UDF features regenerate successfully and the User Defined Feature Placement dialog closes.