When using SolidWorks to design a part to be waterjet cut, you will need to create a drawing file from the part.
Let's take a look at a part designed in SolidWorks which we want to cut. The part is open in SolidWorks in the picture below.

Illustration : A part in SolidWorks

To turn this into a drawing, choose File | Make Drawing from Part from the menu.

Illustration : Creating a drawing

A dialog box will appear. Make sure you have un-checked the “Display sheet format” box, then click the OK button.

Illustration : Removing the sheet format

The drawing sheet will appear. Drag the drawing view (1) onto the drawing (2). You will typicaly want the Top or Bottom view. You should then press the escape key or click the green checkmark to indicate that you are done adding drawing views.

Illustration : Adding the part view (1) to the drawing (2)

You then need to make sure that the drawing scale is set correctly. Click on the drawing view within the drawing. Then choose the “Use custom scale” radio button and pick “1:1” scale from the drop down list on the panel.

Illustration : Setting the part scale in the drawing

Finally, you should save the file in a format that's compatible with the waterjet cutting system. Most waterjet cutting systems accept the DXF file format. Choose File | Save As... from the menu. Pick DXF from the “Save as type” drop down list. Enter the file name and click the Save button.

Illustration : Saving the drawing

At this point, you now have a file which can be used to turn your SolidWorks design into a real part.