:topic: Oblique Reslicing

.. index::
   triple: DREAM3D-NX; Quad View; Oblique Reslicing

.. _QuadViewOblique:

Oblique Reslicing
##################

**In this section we describe how to use the oblique reslicing feature
to rotate the slice planes off of the standard axes.**

By default, the Quad View module operates in **axis-aligned mode**, where
the three slice planes are locked to the X, Y, and Z axes. This ensures
that Windows 2–4 always show true orthogonal cross-sections of the data.

The **Oblique Reslice** feature allows the slice planes to be freely
rotated to arbitrary angles, enabling the user to cut through the data
along any orientation. This is useful for examining features that are
not aligned with the standard axes.

Axis-Aligned Mode (Default)
==============================

In axis-aligned mode (the default), the slice planes cannot be rotated.
The crosshair axis lines in Windows 2–4 can still be dragged to
reposition the planes along their respective axes, but no rotation is
possible.

.. figure:: Images/60_ObliqueReslicing/AxisAlignedMode.png
   :alt: Axis-Aligned Mode

   Axis-Aligned Mode — Planes Are Locked to the Standard Axes

Enabling Oblique Reslice Mode
================================

To enable free rotation of the slice planes, check the **Oblique
Reslice** checkbox in the **Controls Panel** on the right side of the
Quad View module.

.. figure:: Images/60_ObliqueReslicing/ObliqueResliceCheckbox.png
   :alt: Oblique Reslice Checkbox

   Oblique Reslice Checkbox in the Controls Panel

Rotating a Slice Plane
========================

In oblique mode, rotating a slice plane is performed using **rotation
arrow controls** that appear in Windows 2–4. These controls are designed
so that clicking on an axis line always translates (moves) the plane,
and rotation is only available through the dedicated arrows.

To rotate a plane:

1. **Hover the mouse cursor over one of the two axis lines** in any of
   Windows 2–4. Two black triangular rotation arrows (outlined in white) will appear —
   one on each side of the axis line at approximately the 1/3 and 2/3
   positions along the line.

   .. figure:: Images/60_ObliqueReslicing/RotationArrowsVisible.png
      :alt: Rotation Arrows Visible on Hover

      Rotation Arrows Appear When Hovering Over an Axis Line in Oblique Mode

2. **Click and drag one of the arrows** to rotate the plane
   associated with that axis line. The plane rotates around the axis
   perpendicular to the view as you drag.

3. Release the mouse button to set the new plane orientation.

   .. figure:: Images/60_ObliqueReslicing/PlanesRotatedOblique.png
      :alt: Slice Planes Rotated in Oblique Mode

      The Slice Planes Rotated to an Oblique Angle

The rotation angles are reflected in real time in the **Yaw**, **Pitch**,
and **Roll** fields of the text annotation overlay (if annotations are
enabled) and in the plane positions visible in the 3D volume rendering
in Window 1.

Returning to Axis-Aligned Mode
================================

To return the slice planes to the standard axis-aligned orientation,
uncheck the **Oblique Reslice** checkbox. The rotation arrows will
disappear and all rotation interaction will be blocked. The planes
themselves retain their current orientation until they are explicitly
repositioned by dragging an axis line.

.. note::

   Rotation angles are saved as part of the Quad View state file.