Preform (Formlabs)

Overview

For a printer to understand a STL file, it needs to be prepared using a "Slicer" - software, which converts the geometry into a long series of coordinates, which the printer can understand.
Formlabs provides their own, open-source software called PreFrom.
Download from: http://formlabs.com/products/preform/
In the following, we will introduce the features that we use and find useful.

PreForm can import models in .stl and .obj file formats.
Launch PreForm and setup your printer.
Select the model of your Printer.
Specify your Material, the type and the version of the resin. (There is an active link in blue at the bottom that can help you identify your resin type.)
Select Layer Thickness (in mm) with the slider. The default value is 0.05 mm, but you can adjust it to 0.1 mm for a faster print or 0.025 mm for a print with the highest resolution.
Click Apply to save the settings and proceed to the next level to modify your model.
Click Print Settings on the bottom bar in the main workspace (see image below) to the change the above settings.

The View Menu is located on the right top corner of the screen.
Zoom in/out using the +/- buttons or the scroll wheel of the mouse.
Rotate the view 90 degrees to the top, left, right and bottom using the arrows.
Click the centre icon to return back to the initial view.
Alternatively: Rotate the view around the model with Right click + drag and Right click + Shift to pan.

Before you start processing, click the model to enable it. It will become blue.
Click the Size icon to resize your model.
You can specify each dimension (X,Y,Z) seperately or change the Scale factor to
resize your model by a certain factor.
Be careful with the units! PreForm assumes they are always in millimeters.
To change them in inches: Edit -> Model units -> in
Alternatively: Click anywhere on your screen and drag to resize the model directly.

Select One-Click Print option and PreForm will complete automatically all the following steps, Orientation, Supports, and Layout.
Then, you have to confirm and send the job to your FormLabs printer from the Print popup window. Check you specified the correct printer and type of resin.
Quite useful if you are not very familiar with 3D printing.

Click the Orientation icon to rotate your model.
PreForm will compute the optimum orientation for a successful print automatically.
Rotate your model in a specific angle in each X,Y,Z axis.
Use the shaded cube icons to flip your model along each axis.
Click the Select Base icon to place a face pointing toward the build platform.
Alternatively: Click anywhere on your screen and drag to rotate the model directly.
It is recommended to allow the PreForm software to compute the model's orientation.

Click the Supports icon to generate supports for your model.
Supports are essential to ensure a successful printing and can become quite valuable in models with complex geometries.
Support structures consist of the following parts: Base, Scaffolding and Tip.
Click Generate All and PreForm will generate supports automatically.
Use the Edit All icon to add and remove supports after auto-generating.
This can be become quite important for complex models.
Density: defines how closely placed is the support scaffolding and the number of touch-points on your part.
Touch-point size: supports connect to the part at the touch-point. Larger touch-points make stronger supports but they are more difficult to be removed after the printing.
Internal supports: You can control whether you prefer automatically generated internal supports or not.

Advanced submenu settings:

Flat spacing: changes the density of supports, being similar to adjusting the density slider.
Slope multiplier: sets the steepest slope value at which the software will start adding support structures to your model. Its value should be increased to add more supports to sloped surfaces.
Base thickness: crucial factor since the base adheres to the building platform and the support structures with the actual model itself are built on top of this.
Height above the base: sets the minimum height of support structures. It can be lowered to reduce the resin usage but it can’t go lower than 2 mm. If it’s too low it may cause support deformation of failure. PreForm recommends a default height value of 5 mm.

Click the Layout icon to move your model to different locations on the build platform.
Your view will be reoriented as you look down on the build platform from above.
Use the duplicates option to make one or more copies of your model.

Before printing use the Slicer in the right part of the screen for a last check on your model.
Check for Overlapping Models, Internal supports, unsupported parts and correct shelling (where it is applicable).