The glinting bright dot on the side of a shiny apple is the pure, un-scattered bounce of the sun from above. Shininess is a material characteristic called 'specularity' in 3D graphics terms; the ability to reflect light en masse with a pure bounce, and not scattering it ("diffusing" it).
- Select an entity in the space (or in the library, but you'll see your effect if its in the space).
- Undock the Property Editor Panel
- Click on the MeshModel dropdown using the arrow on its left to expand the menu
- Click on Materials
- Select the Underlined Material in the window on the right
- This will bring you to the property editor for the Material currently applied
- Select Specular on the list on the left
- Change the value for the Specular Level under the Specular property on the right side of the panel. The more specular, the more shiny.
- Shine on!
More on specularity: