When printing using translucent materials, the infill pattern can add beauty to the printed object as well as strength.
Using the current system, there's not much options when it comes to printing translucent material where you want the infill to look beautiful. There's only so much you can do by specifying the angle of straight lines used to infill different layers. With "Use random infill placement" turned off, a pattern of 0, 60, -60 looks nice, like a bunch of triangles. -45,45 or 0,90 looks nice, like boxes. But these are all still straight lines on a layer basis, not actually shapes being drawn on each layer.
There's been some discussion in another thread about having honeycomb infill, because of its strength, and it was brought up that this infill pattern might be patented (really?). If so, I can see the reason for not including it. But to get around this, Simplify3D could allow users to define their own custom patterns.
CUSTOM 2D INTERNAL INFILL PATTERNS
There are many different ways of implementing this. A simple way would be to allow users to enter the pattern using a series of X/Y "move to" and "line to" coordinates in a text editor. The coordinate boundaries could be a simple 100x100 grid.
For example, if I wanted to create a triangle-like infill pattern I would have something like:
MoveTo: 00, 99
DrawTo: 49, 00
DrawTo: 99, 99
DrawTo: 00, 99
If I wanted a hexagon to make a honeycomb structure (the strongest connecting regular polygon shape) I could define that using a different set of coordinates.
This system of coordinates is pretty basic. Something a little more complex and flexible could be used instead, such as points and angles, or freehand drawing, etc.
CUSTOM 3D INTERNAL INFILL PATTERNS
For the ultimate in infill control, I would love to be able to define the infill pattern as a 3D object. Maybe an STL file that could be loaded, that Simplify3D simply repeats inside your printed object as infill. For example, lets say that I wanted to beautify my translucent print using pyramids as an infill structure. I would load an STL file of a 3D pyramid structure, set the infill percent, and then Simplify3D would scale it accordingly and repeat it throughout my 3D print.
This might not be all that simple to do, but it would be fantastic for transparent prints.