3.6. Cutting Tools

To build a polygon

1. Activate the Polygon Cut tool.
2. Click the left mouse button to set the apices of the polygon marking the figure to be cut, except the last point.
3. Fix the last point by right-clicking the mouse.
4. To cancel an incomplete building, press Esc.

To build an area with smooth borders (Lasso mode):

1. Activate the Polygon Cut tool.
2. Press and hold the Shift key on the keyboard.
3. Circle the area to be cut holding down the left mouse button.
4. To complete the building release the left mouse button or click the right mouse button.
5. To cancel an incomplete building, press Esc.

1. Grow from surface (mm). The tissue surrounding deleted area will be deleted too. This parameter specifies the distance from the surface on which the tissue will be deleted. If this parameter is set to zero, model surface may look rough, so use a value of zero only if necessary.
2. Min object thickness (mm). If the value is greater than zero, the tissue with a thickness less than the set value will be ignored during deletion.

This parameters for each tool are set separately.

To activate/deactivate the tool, click on the left side of the tool button. If any tool is activated, the button is highlighted.

To cut tissue:

1. Activate the Brush cut mode by clicking button.
2. Set the tool diameter, moving the mouse holding the left button and Alt key.
3. For the Cylinder mode set the height if it is necessary. To do it, click the arrow on the right side of the tool button and select the Cylinder settings... item. In the dialog box that appears set the cut height.
4. Click the left mouse button in the place where you want to cut tissue. Part of the tissue will be cut. The green dot indicates where the great circle of the sphere (the base area of the cylinder) touches the surface of the model. The great circle passes through the center of the sphere and is parallel to the plane of the screen.
5. Repeat steps 3 and 4, if necessary.

Brush restore tool allows you to perform the reverse process of brush cutting.

The Grow (dilation) Shrink (erosion), Fill and Cut invisible volume tools allow to edit tissue within the special algorithms. The Multi-segment growing tool allows you to edit segmented structures. To select one of these tools, click the arrow on the right side of the tool buttons. The button will look different depending on the tool that was used last:

	Grow (dilation) (set by default)
	Shrink (erosion)
	Remove noise (opening)
	Remove holes (closing)
	Multi-segment growing
	Fill
	Cut invisible volume

The Grow (dilation) tool allows you to increase the volume by a certain value from the surface for 1 iteration. This value is specified in the Settings menu of this tool (parameter Growing radius). The increase is possible only within the original volume, for example, after the use of cutting tools. When you use this tool to edit a segmented structure, an increase is possible only within the mask. The tool is used to fine-tune the structure, if initially the required volume was not obtained.

The Shrink (erosion) tool performs the opposite action. The reduction value is specified by the parameter Growing/Shrinking radius.

The Remove noise (opening) tool allows to remove noise from the volume. This tool is equivalent to consistently applied tools Shrink (erosion) and Grow (dilation).

The Remove holes (closing) tool allows to remove little holes from the volume. This tool is equivalent to consistently applied tools Grow (dilation) and Shrink (erosion).

To undo or redo the last action associated with cutting, use the Undo and Redo buttons.