Gravity Sketch is an excellent virtual reality 3D sketching and modelling application that continues to be developed apace with new updates to its interface regularly. As a result of this heady momentum, new tools and features are appearing all the time and sometimes it can be a little unclear initially as to how they should be used. One such tool is the first tool in the Gravity Sketch Tool Belt as its layout currently stands: the Normals tool
What the Normals tool does
The Normals tool is only used with objects and surfaces that are being manipulated via the subdivision or SubD modelling interface in Gravity Sketch. Intersecting the head of the Normals tool with a surface of a SubD object will see this head turn red. By pressing the trigger on the same hand controller you are holding the tool with then allows you to flip the normals of that SubD surface to point out from the opposite side. By flipping the normals, one is essentially flipping which side of the surface of the SubD object is considered the 'outside' and which side is considered the 'inside'. This can be important when importing the object into other modelling software and when turning the 3D model into a real-world object, for instance, through 3D printing.
How can you tell which way the normals are pointing?
Importantly in Gravity Sketch, inside and outside surfaces of SubD surfaces are visually differentiated by transparency. Inside surfaces are transparent, while outside surfaces (from which the normals point outwards) are opaque.