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Spin Dup

Unlike the preceding tool, Spin Dup is not an extrusion tool. In fact, it is a bit to Duplicate what is Spin to Extrude Dup: it makes n copies of the selection, and spread them in a circular pattern around the 3D cursor. As usual, you have to check/set its options before applying it:

• The point of view will determine around which axis the copies are spread…
• The position of the 3D cursor will be the center of the rotation.
• The Degr numeric field specifies the angle “swept” by this tool, in degrees (e.g. set it to 180 ° for half a turn).
• The Steps numeric field specifies how many copies will be duplicated along the “sweep”.
• The Clockwise toggle button control the direction of rotation (as you might have guessed, clockwise when enabled and counter-clockwise otherwise).

Examples

Clock Marks

The Spin Dup tool is a great way to quickly make a series of copies of an object along a circle. For example, you have modeled a clock, and you now want to add hour marks. Model just one mark, in the 12 o’clock position (Hour mark indicated by the arrow). Select the mark and switch to the Editing context with F9.

Set the number of degrees in the Degr: NumButton in the Mesh Tools panel to 360. We want to make 12 copies of our object, so set the Steps to 12 (Spin Dup buttons).

Now:

• Switch the view to the one in which you wish to rotate the object by using the keypad.
• Position the 3D cursor at the center of rotation. To place the cursor at the precise location of an existing object or vertex, select the object or vertex, and press ⇧ ShiftS » Cursor -> Selection.
• Select the object you wish to duplicate and enter Edit mode with ⇆ Tab.
• In Edit mode, select the vertices you want to duplicate (note that you can select all vertices with A or all of the vertices linked to the point under the cursor with L). See (Mesh selected and ready to be SpinDuped).
• Press the Spin Dup button. If you have more than one 3D Window open, you will notice the mouse cursor change to an arrow with a question mark. Click in the window in which you want to perform your rotation. In this case, we want to use the front window (View selection for Spin Dup).

If the view you want is not visible, you can dismiss the arrow/question mark with Esc until you can switch a window to the appropriate view with the keypad.

View selection for Spin Dup.

When spin-duplicating an object 360 degrees, a duplicate object is placed at the same location of the first object, producing duplicate geometry.

You will notice that after clicking the Spin Dup button, the original geometry remains selected. To delete it, simply press X » Vertices. The source object is deleted, but the duplicated version beneath it remains (Removal of duplicated object).

If you like a little math you need not bother with duplicates because you can avoid them at the start. Just make 11 duplicates, not 12, and not around the whole 360°, but just through 330° (that is 360×11/12). This way no duplicate is placed over the original object.

In general, to make n duplicates over 360 degrees without overlapping, just spin n-1 objects over 360×(n-1)/n degrees.

(Final Clock Render) shows the final rendering of the clock.

Final Clock Render.