Doc: Update docs for split view

- Described using the new viewport modes in 3D.

Fixes: QDS-15390
Change-Id: I1a21bf37ac50648d6f4b60dbe15a840ba836b722
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Mats Honkamaa <mats.honkamaa@qt.io>

doc/qtdesignstudio/src/qtquick3d-editor/qtdesignstudio-3d-editor.qdoc

@@ -122,15 +122,30 @@
 
     \section2 Using the split view
 
-    To view the scene in a split view of four different point of views, select
-    \imagesplitview.
+    Use the split view to view the scene from different points of view using the different
+    viewport modes.
 
-    \image studio-3d-split-view.webp "Split view in the 3D view"
+    To view the scene in a split view, select \imagesplitview (\uicontrol {Show Viewport Modes})
+    and then select one of the viewport modes:
+    \list
+        \li The \uicontrol Single mode shows the scene in one pane from a single point of view.
+        \li The \uicontrol Quad mode shows the scene from four different points of view using
+            four panes.
+        \li The \uicontrol {3 Left 1 Right} mode shows the scene from four points of
+            view using three smaller and one larger pane.
+        \li The \uicontrol {2 Horizontal} mode shows the scene from two points of view using
+            two horizontal panes.
+        \li The \uicontrol {2 Vertical} mode shows the scene from two points of view using
+            two vertical panes.
+    \endlist
 
-    Select one of the four panes to make it the active pane. The active pane is marked with
-    a blue frame. Use the world axis helper to change the point of view for each pane
-    independently. Navigate each split by panning, rotating, and zooming, as
-    described above.
+    Select one of the panes to make it the active pane. The active pane is marked with a blue frame.
+    Use the world axis helper to change the point of view for each pane independently. You can
+    \l {Toggling the camera mode}{toggle the camera mode} between the perspective and orthographic
+    modes independently for each pane. \l {Navigating in the 3D scene}{Navigate} each split by
+    panning, rotating, and zooming. To resize the panes, drag the border between them.
+
+    \image {studio-3d-split-view.webp} {Split view in the 3D view.}
 
     \section2 Using the fly mode