inkscape-manual

Handling vanishing points
Adjust the vanishing points of a perspective by dragging them on the canvas (see below) or
toggling their states; all boxes sharing this perspective are affected by a vanishing point
move.
When several boxes are selected, all vanishing points of their associated perspectives are
shown on the canvas. If vanishing points of different perspectives coincide, they are
combined in a single "dragger". Moving this dragger moves all the vanishing points
simultaneously and transforms the associated boxes accordingly. Note that some non-selected
boxes may also be reshaped if their perspectives share the same vanishing point. Pressing
Shift while moving the dragger can be used to only transform the selected boxes, separating
their perspectives from the non-selected ones'. On the other hand, when a vanishing point
being dragged comes close enough to another one, both snap together and are combined in a
single dragger.
Rotating perspective lines
The various kinds of parentheses, namely [ ], ( ), { }, can be used to rotate infinite (i.e.,
parallel) perspective lines in X-, Y-, and Z-direction, respectively. Closing parentheses rotate
clockwise and opening parentheses rotate counterclockwise. The angle of rotation is taken
from the preferences. Pressing Alt reduces the amount of rotation to 1 screen pixel.
Changing mode of perspective lines
Tips
When the 3D box tool is active, Shift+X, Shift+Y, and Shift+Z toggle perspective lines in
the corresponding direction between "converging" and "parallel".
Inside 3D Box tool
In SVG, a 3D box is represented as a group (svg:g) with a special extension attribute (in
Inkscape's namespace); this group contains the 6 quadrilateral paths representing the sides of
Moving a 3D box 35