Reslice

The Reslice tool resamples the volume and mask datasets along an arbitrary plane. A line drawn in a slice view defines the in-plane direction, and the same plane is shown in the 3D view where it can be rotated interactively before export or final application.

Reslice vs Swap Axes

• Reslice resamples the data along any arbitrary plane orientation, including oblique angles.
• Swap Axes only exchanges two of the three principal axes without interpolation.
• Use Reslice when you need a non-orthogonal reorientation.
• Use Swap Axes when you only need to exchange two principal axes.

Accessing the Tool

1. Navigate to the Image tab in the ribbon.
2. Click Reslice in the Transform section.

Controls

Control	Description
Description	Brief usage guidance for defining the reslice plane from a slice-view line and refining it in 3D.
Plane Orientation	Resets the reslice plane to the selected axis-aligned orientation (YZ, XZ, or XY) and clears the current line and offset. The embedded preview always shows the resliced plane after the reset.
3D controls	Chooses which 3D plane controller is used to refine the reslice plane. Transform Gizmo uses the existing plane markup with gizmo handles. Plane Handles uses the plane widget for direct plane dragging.
Slice Offset slider	Moves the reslice plane along its normal direction. This is a fast adjustment control linked directly to the spin box.
Slice Offset (mm)	Precise numerical version of the offset control. Preview, export, and apply all use the same offset value.
Show plane in 3D view	Shows or hides the currently selected 3D plane widget in the 3D view.
For volume(s)	Selects the interpolation used for the resliced volume preview and for the applied reslice on volume data.
For mask(s)	Selects the interpolation used when the reslice is applied to mask data.
Resliced preview	Live 2D preview of the current resliced volume. It updates when the line, plane, offset, preview plane, or volume interpolation changes.
Export Slice	Writes the currently previewed reslice slice as a single image file using the active volume's current window and level.
Export All Slices	Opens the image-series export dialog for the current resliced volume and preselects full-stack export.
Apply	Reslices all volume and mask objects to the current plane orientation and offset.

Parameters

Plane Orientation

Resets the reslice plane to the selected axis-aligned orientation:

Option	Effect
Plane 1 (YZ)	Resets the reslice plane to the YZ orientation (normal along X)
Plane 2 (XZ)	Resets the reslice plane to the XZ orientation (normal along Y)
Plane 3 (XY)	Resets the reslice plane to the XY orientation (normal along Z)

Changing this option resets the reslice plane to the chosen axis-aligned orientation, clears any drawn line, and resets the slice offset to 0. The embedded preview always shows the resliced plane after the reset.

3D Controls

Select which widget is used to manipulate the reslice plane in the 3D view:

Option	Effect
Transform Gizmo	Uses the existing plane markup together with gizmo handles for 3D refinement.
Plane Handles	Uses the plane widget for direct plane manipulation in the 3D view.

Switching this option changes only the 3D plane controller. The underlying reslice plane, preview, export, and apply pipeline remain the same.

Slice Offset

Moves the current reslice plane along its normal direction, in millimeters. The plane shown in 3D, the live preview, the exported slice, and the applied reslice all use the same offset.

Show Plane in 3D View

Toggle the visibility of the currently selected 3D plane widget. When visible, you can refine the reslice orientation with either the Transform Gizmo or the Plane Handles controller.

Interpolation Method

Option	Description
Nearest	Nearest-neighbor interpolation — fastest, no blending, best for masks
Linear	Trilinear interpolation — good balance of quality and speed
Cubic	Tricubic interpolation — highest quality, slowest

Separate interpolation methods can be chosen for volumes (default: Linear) and masks (default: Nearest).

Workflow

1. Open the Reslice tool from the Image tab.
2. Draw a line in one of the orthogonal slice views.
3. Optionally choose Transform Gizmo or Plane Handles as the 3D control mode.
4. Review the synchronized plane in the 3D view and the live preview in the embedded viewer.
5. Optionally refine the plane in the 3D view.
6. Adjust Slice Offset to move the plane along its normal.
7. Optionally click Export Slice to save the current preview slice.
8. Optionally click Export All Slices to export an image stack from the current resliced volume.
9. Click Apply to reslice all volumes and masks to the new orientation.

Resliced Preview

The embedded 2D viewer shows a real-time preview of the current resliced volume from the active volume. The viewer always shows the resliced plane itself (the plane defined by the current line and 3D adjustments). The preview updates when the line, the 3D plane, the slice offset, the preview plane selection, or the volume interpolation method changes.

Interaction Notes

• Only one driver line is active at a time.
• Starting a new line replaces the previously drawn line.
• Changing the source slice in the line's owning slice view clears the driver line; draw a new line on the new slice to redefine the reslice plane.
• Changing Plane Orientation resets the reslice plane to the selected axis-aligned orientation and clears the current line and offset. The preview always shows the resliced plane.
• Changing 3D controls switches only the 3D controller; it does not change the current reslice plane by itself.
• Moving the active 3D plane widget updates the live preview immediately.

Geometry Model

• The line lies on the reslice plane. It is not the plane normal.
• point0 -> point1 defines the in-plane x-axis used by both preview and final resampling.
• The slice-view normal supplies the second geometric constraint needed to define the plane.
• The plane normal is computed as the cross product of the line direction and the active slice-view normal.
• point0 anchors the plane definition in the active slice view.
• The displayed line segment and the displayed plane extents are clipped to the volume bounds so they do not expand beyond the image domain.

Use Cases

Oblique Reformatting

When the anatomy or feature of interest is not aligned with the original scan axes:

1. Draw the line along the feature in the slice view that best shows it.
2. Optionally refine the result by rotating the synchronized plane in 3D.
3. Verify the orientation in the preview.
4. Apply to reformat the entire volume along the new axis.

Exporting Individual Slices

Use Export Slice to save the currently previewed reslice slice as a 2D image file for reporting or further analysis. The exported image uses the current display window and level from the active volume.

Exporting All Resliced Slices

Use Export All Slices to open the image stack export dialog for the current resliced volume. This exports an image series from the resliced volume using the current display window and level.

Affected Objects

Reslicing affects:

• All volume objects
• All mask objects

Both are resliced together to maintain spatial correspondence.

Scripting

The scripting API is unchanged by the 3D controls selector. The selector only changes how the plane is manipulated in the UI; the underlying reslice operation still uses the same plane origin, plane normal, and interpolation settings.

import ScriptingApi as api

app = api.Application()
volume_operations = app.get_volume_operations()

# Reslice along Plane 1 (YZ)
volume_operations.reslice(
    ["Volume 1"],
    [0.0, 0.0, 0.0],           # planeOrigin [x, y, z]
    [1.0, 0.0, 0.0],           # planeNormal [nx, ny, nz]
    api.Interpolation.Linear,  # volumeInterpolation
    api.Interpolation.Nearest  # maskInterpolation
)

# Reslice along an oblique plane
import math
n = 1.0 / math.sqrt(3.0)
volume_operations.reslice(
    ["Volume 1"],
    [0.0, 0.0, 0.0],
    [n, n, n],
    api.Interpolation.Cubic,
    api.Interpolation.Nearest
)

warning

Reslicing resamples the data onto a new grid. Any associated metadata describing the original orientation (such as DICOM orientation tags) will be removed. Verify the orientation in the slice views after applying the operation.

See also: Swap Axes, Flip, Resample