The Additive Prep application is implemented as a tab in SpaceClaim. You need to have an appropriate license for the Additive tab to appear. Additive Prep is included with Additive Suite and Additive Print licenses. It is also available separately as an add-on to SpaceClaim. See your Ansys Channel Partner to find out about your licensing options.

Even if you have a proper license, the Additive Prep application is not enabled by default. To enable the application, in SpaceClaim, click File > SpaceClaim Options > License and then check Additive Prep. Click OK. (If the Additive Prep option appears grayed out, it means you do not have a proper license.) The option is "sticky" in that once you have checked the box, it will remain checked each time you open SpaceClaim, until you clear the box.