Pixyz Review viewer is where 3D files are displayed and can be manipulated or custom (selection, transformation, visibility...):

• Scene axis: Pixyz Review viewer is Y-up oriented, and right-handed. Red is the X-axis, Green is the Y-axis, Blue is the Z-axis ([X,Y,Z] > [R,G,B]).
• Scene HUD : The number of occurrences and triangles are are displayed accordingly to the scene and selection. It also displays if it you're working on a Variants or not. 
• Scene grid: Brings a visual help to evaluate objects orientation and objects scale. By default, the grid size is 5 meters large.

Related topics:

• Navigation controls
• Selection controls
• Scene View Effects
• Set environment for specific lighting & background
• Preferences