Support material is necessary to print overhanging elements within a model. Most FDM printers generate a lattice or grid support structure. These structures are beneficial because they are universal. However, if only points of a model are beneath the overhang threshold, tree supports can be used.
Tree supports are adjustable support structures which are most commonly found in SLA (resin) printing. Tree supports are point supports. This means they are most beneficial if only a small portion or point of the model is beneath the overhang threshold.
The potential advantages of using tree supports are:
More control over support placement
Possible shorter print times with less filament wastage.
Lattice Supports can easily be generated in slicing software such as Makerbot Print, simply by ticking
As shown in Figure 1.0, these supports may be unnecessarily extensive.
Autodesk Meshmixer is a free software which can be used to generate smart or tree supports. A model which has been exported from Rhino3d or a similar software as an
.obj can be imported in to Meshmixer.
In the main menu in Meshmixer, choose
[import] and select your
Analysis > Overhangs.
To start, we recommend an angle threshold of 45°. This support angle refers to the degree a printer is capable of printing without generating supports.
In general, the larger the angle threshold, the more supports will be generated. An angle threshold of 0° will mean that no supports will be generated, whereas an angle threshold of 90° will mean a layer completely on top of the last will require supports.
Generate supports by selecting
 Generate Support. In our scenario, a singular support has been generated at the base of the Thinker's knuckles.
Printing with tree supports can result in significant reductions in print time and filament usage. In this case, filament usage was reduced by 12% (from 16.71g to 14.74g) and the print time was reduced by 18% (from 1h 32m to 1h 16m). These savings can add up for larger prints.
The tree supports also resulted in less scarring on the surface of the print.
The following webpages may also be of use when considering smart supports.