About a Lip Feature
You can create a lip feature on mating surfaces of two different parts in an assembly to ensure that the interlock geometry is the same on both parts. A lip is created as a protrusion on one part and a cut on another.
A lip is not an assembly feature—it must be created on each part separately. You can set appropriate connections between dimensions on both parts through relations and parameters.
A lip is constructed by offsetting the mating surface along the selected edges. The edges must form a continuous contour, either open or closed. The top (or bottom) surface of the lip copies the geometry of the mating surface; you can draft the side surface with respect to the lip direction.
Lip direction (the direction of the offset) is determined by the normal to a reference plane. The draft angle is the angle between the normal to the reference plane and the side surface of the lip.
The following figure shows the lip feature parameters.
1. This surface repeats the shape of the mating surface
2. Draft angle
3. Mating surface (could be reference plane too)
4. Side offset
5. Selected edge
6. Lip offset
Usually, the reference plane is coincident with the lip (mating) surface. You must select a separate reference plane in the following cases:
• The mating surface is not a plane.
• You want the lip creation direction not to be normal to the mating plane. The lip feature will then be distorted.
At any point of lip feature creation, the normal to the mating surface must be either coincident, or form a slight angle with the normal to the reference plane. The closer the normals, the less the lip geometry distortion.