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Interpolate 3D

The Interpolate 3D tool fills gaps between segmented slices by generating intermediate mask data. When segmentation is performed on every Nth slice, interpolation completes the mask in the intervening slices.

Accessing the Tool​

  1. Navigate to the Segmentation tab in the ribbon.
  2. Click Interpolate 3D in the Operations section.

How It Works​

The algorithm analyzes segmented slices and generates intermediate contours:

  1. Identifies slices containing mask data (key slices).
  2. Analyzes the mask contours on each key slice.
  3. Generates interpolated contours for slices between key slices.
  4. Fills the interpolated contours to create mask voxels.

The interpolation considers the shape and position of contours on adjacent key slices to create smooth transitions.

Parameters​

Target Object(s)​

OptionDescription
Active maskInterpolate the active mask only.
Selected masksInterpolate all selected masks.
Visible masksInterpolate all visible masks.
All masksInterpolate every mask.

Interpolate Along​

OptionDescription
All axes (default)Interpolate in all three directions.
XInterpolate along the X axis (between sagittal slices).
YInterpolate along the Y axis (between coronal slices).
ZInterpolate along the Z axis (between axial slices).

Workflow​

  1. Segment key slices manually or with other tools.
  2. Open the Interpolate 3D tool from the Segmentation tab.
  3. Select the Target Object(s).
  4. Choose the Interpolate Along axis.
  5. Click Apply to generate interpolated slices in empty slices.

Use Cases​

Manual Segmentation Acceleration​

Speed up manual segmentation workflow:

  1. Segment every 5th–10th slice using Edit Mask.
  2. Apply Interpolate 3D to fill gaps.
  3. Review and correct the interpolated slices.

Sparse Segmentation Completion​

Complete masks where only partial slice segmentation exists:

  • Clinical segmentation where only representative slices are marked.
  • Existing segmentations with missing slices.

Tips​

  • Segment slices where the shape changes significantly (key anatomical landmarks).
  • More key slices near complex regions improve interpolation accuracy.
  • Review interpolated regions and manually correct if needed.
  • Use in combination with smoothing for better boundary quality.
tip

For structures with complex shapes, segment more densely in regions where the contour changes rapidly, and more sparsely in uniform regions.

Limitations​

  • Works best with relatively smooth shape transitions.
  • Branching structures may not interpolate correctly.
  • Very large gaps may produce inaccurate results.

See Also​