Define here the projection parameters applied by default when creating a new layer.
Perspective, Orthographic
Set the projection that is applied by default when creating a new layer. 
GAMGI projects the 3D layer space on the 2D screen using 
Perspective
or 
Orthographic projections. The 
Perspective projection
is better to simulate realistic views, but the 
Orthographic
projection preserves object dimensions, as these are not distorted
by perspective.
Near, Far, Top
Set the dimensions of the space volume that by default 
is visible to the observer, after being projected into the 
window graphic area.
This projection volume has six faces, and the front and back faces 
are always perpendicular to the viewing direction. 
Near and
Far set the default distances from the observer to these front 
and back faces, corresponding to the minimum and maximum distances 
that the observer can see. 
Near must be smaller than 
Far.
In a 
Orthographic projection, the projection volume is a rectangular
parallelepiped, so the 4 lateral faces are paralell and perpendicular to
each other. In a 
Perspective projection, the projection volume is
a truncated quandrangular pyramid, with the apex at the view point.
Top defines the half-height of the front face of the projection 
volume. The width is automatically determined from the ratio height / width 
of the window graphic area, so everytime users resize this window, the 
projection volume changes accordingly. Increasing 
Top increases 
the visible volume and decreases the size of the objects.
Each layer has its own projection parameters, so in a window with
multiple visible layers, the image rendered in the graphic area 
is the superposition of the various, totally independent, layer 
views.