Advanced Support Structure Settings

PreForm Software is designed to take the hard work out of generating support structures so that you can focus on creating great models and prints. 3D printing is as much an art as it is a science, so we’ve designed more advanced support structure options to give you greater control. Keep in mind that adjusting these settings can affect your print for better or worse.

Click the Supports icon (third down in the PreForm toolbar) to access additional features.

Support setting toolbar in PreForm

The circular arrow button next to the advanced tab will restore the default setting values.


This slider allows controls how closely-packed the support pillars are, and also affects how many contact points there are between the support structures and your model. Changing the density will also adjust the flat spacing value, which measures the distance between touchpoints on a flat, horizontal surface.


Printing in flexible resin may require higher support density if you model has a large cross section. See our guide on Using Flexible Resin to ensure that your flexible models print successfully.

Touchpoint Size

Touchpoints are the locations where each support connects to the part. By default, this point has a smaller radius than the rest of the support structure, which allows for easier removal and fewer marks after printing. There are trade-offs to increasing or decreasing the touch point size:

  • Smaller touchpoints make it easier to remove the support structures from the printed part, and will leave fewer marks on the build. However, there is a higher chance of the support teeth failing to hold up the part while printing, resulting in build failure.
  • Larger touchpoints make for more security of the supports during printing, but the supports will be harder to remove from the finished part.


Setting the touchpoint size below 0.40 mm may offer smoother print surfaces, but parts may separate from supports with a point size below 0.40 mm. For small touchpoints, increasing the density value may slightly improve the print quality. Gain printing experience and practice identifying critical support positions before lowering the touchpoint size.

Internal Supports

Checking this box will generate supports inside your model, to shore up overhangs and other difficult geometries.

Unsupported regions of a model render with red

Without internal supports, the top legs of the sample table model are unsupported (indicated by the deep red region on the PreForm render) and may fail in a build. If this is the preferred orientation to print the part, it's necessary to add internal supports.

Fully supported model with internal supports and no red shading

With internal supports added, the full structure is sufficiently supported and should print without issues.

Form Tip

As supports are generated or edited, PreForm can help identify regions that may require additional support. While the red shading is a tool to guide support “neediness,” you may find other support settings to be equally effective.

Editing Supports

PreForm allows support structures to be manually edited. This feature is especially useful for small features that require support to print successfully, which PreForm may not recognize. In the example of the snail, the shell required manually adding extra supports in order to be fully supported.

The “Edit All” option opens PreForm’s manual support editor. This tool provides the liberty to make custom adjustments to PreForm’s auto-generated supports by revising the contact points of the supports. Your cursor operates as the primary tool.

Red shading indicates your model needs additional supports, which can be added manually.
Hovering over a support will turn it red. Click once to remove.
Hold Shift + Scroll on your mouse to adjust the point size of the support.
Slicer tool
The slicer tool allows you to see inside your model and place internal supports.

Adding and Deleting Manual Supports

Create supports by clicking on the surface of the model. To remove a contact point, click the contact point once. Supports can be added to any visible surface that faces the build platform, at intervals of 1.5 mm or larger. When manually adding supports, the touch-point size slider works identically to the automatic support generator. You can also edit touch point size for individual supports by holding down shift and scrolling on your mouse.

Internal supports can also be added, as long as the cavity or gap is visible. The layer slicer is enabled in manual support editing mode, but is upside down to allow visibility into the model.

Applying Support Edits

When you are done manually editing the supports, click “Apply Changes” to generate the additional supports. Once you exit the support editor, PreForm will apply the modifications to the model, revealing the newly generated supports and any modifications to the base. To continue revising individual supports and contact points, re-open the support editor.

Flat Spacing

Flat spacing is a measure of the spacing between support pillars. The measurement is set by adjusting the density slider. For standard resins, the default support density will generate a flat spacing measurement of 5.0 mm.

Slope Multiplier

Adjusting the slope multiplier changes the density of supports for sloped and angled surfaces. The default value for slope multiplier is set to 1.0 mm. The slope multiplier is a coefficient that can be set between 0 and 5.0 mm, in increments of 0.01 mm.
- A low slope multiplier (ie: less than 1.0 mm) will generate fewer supports on sloped surfaces, with more spacing between supports.
- A high slope multiplier (ie: greater than 1.0 mm) will increase the number of supports on angled surfaces.

From left to right: slope multiplier at 2.0, 1.0, 0.5

Base Thickness

All prints start with a base that adheres to the build platform. Support structures and the models themselves are created on top of the base layers. When adjusting the base thickness, keep in mind that a thinner base may affect support structure stability, while a thicker base may be difficult to remove from the build platform. Because of normal compression that occurs between the build platform and tank during the first layers, the base thickness that you set in the advanced support settings will usually be between 1.5 mm and 2.0 mm. The default base thickness value is 2.0 mm.

Height Above Base

This value indicates the minimum height of support structures - the smallest distance between the part and the base. The default value and Formlabs’ recommended minimum is 5.0 mm; PreForm will reject any value 2.0 mm or less. If this minimum support height is too small, supports on parts with large surface areas may fail or deform due to normal shrinkage.

Contact Support

Questions? Get in touch.