You can model while in perspective mode without defaulting to orthographic mode.

Release: Creo Parametric 5.0.0.0

You can also watch this video on the PTC Learning Connector: Designing in Perspective

When working in Part and Assembly modes, you can maintain perspective display mode when modeling. From the View tab, click Perspective View to easily toggle between orthographic and perspective mode or use the In-graphics toolbar.

Perspective is the way in which models appear to the eye depending on their spatial attributes or their dimensions, and the position of the eye relative to the models. This enhancement helps you to model your design in a realistic view.

The ability to control the perspective display settings using Focal Length (mm), Eye Distance (Dolly), and Image Zoom continues to be available. These settings are maintained for the session and are used when modeling if perspective mode is active.

These enhancements help designers to design and visualize products as the products would appear in the real-world.