From exocad documentation
The 'Free-Forming' window gives you access to the following features:
- Anatomic forming: Changing the shape of the tooth anatomy, while taking advantage of the intelligent library models
- Virtual wax knife - adding or removing material, smoothing
- Adaptation of chewing surface to the antagonist, contacts to the adjacent teeth, and pontics to the gingiva
- Paint & Pull
- Attachment Editor
Click & drag on the tooth to change its shape.
During free-forming, it's very useful to visualize distances to antagonists or adjacents - see section "Visualizing contacts and occlusions" for details.
|Use the buttons - to change the area that you're editing:
By expanding the 'Advanced options', you can access two options allowing you to restrict the movement in certain ways. Using Movement , you can restrict movements to occlusal direction (up/down) only. Using Hold parts fixed , you can hold certain parts of the tooth fixed, either the cusp tips or the equator.
Free-Forming Adjustments – Adding or Removing Material, Smoothing
Click the 'Free' tab to switch to the "Virtual wax knife", which allows you to add or remove material. You can toggle between Add/Remove  material and Smooth/Flatten .
To add or remove material, click on the tooth and hold Add/Remove . The longer you hold it, the more material will be added.
Activate Smooth/Flatten , click and hold the mouse button on the parts you'd like to smooth.
Adjusting the Brush
Using the slider Strength , you can adjust the speed at which material is added or removed while you hold the mouse button (or the amount of smoothing when in "Smooth/Flatten" mode). The slider Brush size  controls the brush size, that is the affected area around the mouse pointer.