Constraints

Along axis

Limit transformation along a single axis.
Define rotation axis.

Usage :

Use keyboard shortcut X, Y, Z or MIDDLE MOUSE to constraint along an axis.

To plane

Will limit transformation to 2 axis on a plane.

Udage :

Use keyboard shortcut SHIFT + X, Y, Z or SHIFT + MIDDLE MOUSE to constraint to a plane .

Along line

Move “snap to” along a segment.

Usage :

While snapping “to”, move your mouse over any line, then enter a value in keyboard.
If your mouse pointer is close to line start, then the value will be measured from that point in the direction of line end.
If your mouse pointer is close to line end, then the value will be measured from that point in the direction of line start.

In direction of line

Move using direction of a line (parallel).

Usage :

Mouse over the line then enter a value on keyboard.
If your mouse pointer is close to line start, the direction will head toward line end.
If your mouse pointer is close to line end, the direction will head toward line start.

Along face normal

Usage :

While snapping “to”, move your mouse over any face, then enter a value in keyboard.
The object will move above surface at snap point from entered value.

Between snap from and snap to

Usage :

While snapping “to”, move your mouse over any point, then enter a value in keyboard.
The object will move in direction of that point of entered value.