Rotation

The rotation tool can be accessed by selecting the object from the second pop-up button or by pressing the E key on the keyboard.

In this case, the arrows in the gizmo will be replaced by three spherical circles highlighted in the colors corresponding to their rotation axes.

From the image above, it is easy to see that the new gizmo is in a specific position, the one related to the pivot, in this case placed on the base of the cube we are using for this demonstration.

What was previously a y axis of vertical movement now becomes a rotation axis, so the translation of each point of the object is no longer linear, but angular on the corresponding plane perpendicular to the axis itself.

It is activated by selecting the circumference of our interest and moving the mouse by the amount of momentum required to achieve the desired rotation. As with the Position tool, mouse interaction will highlight the reference in yellow, and clicking will initiate the action.

Again, the information block in the middle will show real-time references relative to the editing operations. In this case, the unit of measurement is the decimal sexagesimal degree, i.e. 360 degrees on the full rotation and a decimal fraction of a degree, so we will see non-unit values indicated by a comma. Similarly, we will be able to manually enter the values we are looking for with the form below, which is very useful when we need to accurately replicate the rotation of multiple objects.

It is possible to enter positive or negative values. Positive values produce a clockwise rotation with respect to the normal of the rotation plane, negative values produce a counterclockwise rotation.

Note: entering negative values will always display the positive counterpart in the information block. For example, if you manually enter a value of -15 with respect to an axis, it will be displayed as 345 after confirmation.

In the following example, the cube is rotated 45° on the y axis.

The pivot is placed at the center of the vertical axis of the cube, but at the base of the cube. The resulting rotation does not significantly change its position or size of the element in the space.

However, we cannot expect the selected element to remain in the same position as it rotates, because the angular movement is determined by the radius, and thus the distance between the object and its pivot. This means that a pivot placed exactly in the center will cause the object to rotate about itself, but a pivot that is unbalanced or outside the object will cause nonlinear motion along a circumferential arc.

Let us return the cube to its original position and see what happens when we apply a rotation on the z-axis instead. We will test two values, rotating it 45° and 90°.

If the pivot point is located at the bottom, i.e. off-center with respect to its height, a rotation along the z-axis produces a rotation with a fulcrum on the pivot itself, which causes the object to lie sideways and also to change its position in space.

The change in position is only perceptual. The object has not actually been moved, because its coordinates always refer to the position of the pivot. By asking the builder about the position of the yellow cube, its value actually remains unchanged.

The movement along the circumference is smooth, with no snap constraints, because the input form can always be used to set specific values. However, there is a mode that allows rotation in predefined steps of 15°, a geometrically very common value because of its regular multiples (related to angle measurements).

To activate the 15° snap, simply hold down the SHIFT key while rotating with the mouse.