# How to use SOLIDWORKS Surfaces as Reference Geometry for Mates

Article by Mehdi Rezaei, CSWE updated October 14, 2016

###### Article

Dummy/reference surfaces can be utilized for various design situations in SOLIDWORKS. Due to the fact that the surfaces have no thickness and do not contribute to the weight or mass properties of the parts or assemblies. Surfaces are useful as reference geometry and can then be hidden from view.  In this blog as describe an example of using dummy surfaces as reference geometry for a mate in an assembly.

## SOLIDWORKS Surface Reference Mate Example

Mating spherical joints in SOLIDWORKS can be a bit of a challenge depending on the required settings and final application. In the following image a handle and a base plate are shown which are connected with a ball joint. A specific movement is required for the assembly. The handle can only move as far as it hits the sealing/edge of the base. The ball on the end of the handle must  always be tangent to the bottom of its seat in the base plate.

Ball Joint Connection

## Dummy surface to assist your mate

There are many techniques to mate the handle and the base plate, but a dummy surface could be modeled in the base plate part file. The assembly requirement in this case is:

• The reddish surface sphere shown in the image below is made to the same size as the handle’s end ball.
• The surface sphere is modeled to be tangent to the center of the seat.
• Finally, in the assembly file, the end ball of the handle needs to be concentrically mated to the dummy surface.

To control the angular movement of the handle, only one more mate needs to be added between the two center lines of the plate and the handle. The angle needs to be measured by turning on the collision detection and moving the handle until it touches the top edge of the sealing/plate. With only two standard mates the ball joint is placed in the assembly.

Ball joint assembly definition

### Other uses for Surfaces

Dummy/reference surfaces can be used for other purposes such as:

• Aligning an edge flange in a sheet metal assembly,
• As a reference for an up to surface extrusion,
• Or as a cutting tool when defining cut with surface, etc.