WHITE PAPER

Preventing suction cups in PreForm

"Cups" refer to hollow volumes or cavities in a model. Hollow volumes and concave geometries require more careful attention to the model orientation.

Pointing the opening of the cavity face upward in PreForm traps air between the part and the resin tank as the build platform lowers the cavity against the bottom of the resin tank during printing.

The resulting suction can cause separation between printed layers, structural defects, warping, and print failures, all of which can contaminate resin, damage the resin tank, or cause resin spills.

Tip:

For models that contain internal or enclosed hollows (e.g., a hollow sphere), use a 3D design software to either fill the hollow or add drainage holes to minimize suction during printing.

Enabling Show Cups in PreForm

Suction cups that reduce printability are highlighted in yellow.

To see suction cups highlighted in yellow:

Click the < button. The Job Info dialog box opens.
Enable Show Cups. The toggle turns blue and suction cups are highlighted in yellow.

Tip:

PreForm 3.32.0 and later: If you are working with multiple models, click the crosshair icon next to Cup Detected to select the model or models with a detected cup.

Resolving suction cups in PreForm

Step 1: Rotate the model with the cavity opening face downward

Rotate the highlighted areas using the Orientation tool so that the opening of the cavity either faces downward or is rotated at an 5–15° angle.

Step 2: Regenerate the supports

When there are no areas highlighted in yellow, regenerate the supports using the Supports tool.

Tip:

To switch the printability display for minima in PreForm, press Option-2 on macOS or Alt+2 on Windows, or click View > Print Validation in the menu bar, and select or deselect Show Cups.