Next, we will apply fixed boundary conditions to the four nodes at the base of the model.
- Click
View 
Navigate Orientation Front View. - With the
Selection Shape Point or Rectangle and 
Selection Select Vertices commands active, click and drag to draw a box enclosing the bottom of the model as shown in the following image. 
- Click
Setup Constraints General Constraint. Notice that the title bar of the dialog box says "Creating 8 Nodal General Constraint Objects." The reason for this is because there are two coincident vertices at each corner of the base, one for each part. - Click the Fixed button.
- Click OK.