# How do I rig each blade to fan out like an aperture lens?

I'm new to blender so I've got loads to learn. My problem at the moment is that I want to rig up each individual triangle, so that I can get it to fan out like a camera aperture. Can anyone help me achieve this?

• It would be better to make one blade and create a radial array. – Denis Sep 16 '15 at 19:52
• @James Skidmore Are you wanting to create an animated iris (perhaps like the iris valve used in the 2nd half of the movie 'Alien'?), that opens and closes to make the aperture larger or smaller? – Mike Metcalf Sep 16 '15 at 21:31
• @MikeMetcalf Yes ideally I want to use it as an eye for a robot character I'm designing and so I'd like to animated the Iris to represent eye interaction – James Skidmore Sep 17 '15 at 7:36

## Copy Rotation Constraint + Local Space

I would move the triangle's origin somwhere along the shortest edge.

Then assing to the object a Copy Rotation Constraint pointing to an empty.

We are only interested in copying the rotation on one axis, in this case the Z axis as the blades are in the XY plane.

Notice that we must also change the Rotation space as in the picture above to transfer the rotation of the empty to the object's Local space.

Then we can duplicate the object and control the individual rotation of all blades with the empty:

• Thank you for this, Carlo. Like James, I'm a complete newbie at Blender. Would you mind explaining to me how you 'duplicate the object' so perfectly in a perfect circle? I've seen a YT demo on creating circular arrays but that requires the empty to be at the centre of the array. How did you duplicate these fan blades about the master blade's apex so exactly? Thanks in advance. VV – VectorVictor Nov 13 '18 at 15:51
• @VectorVictor I used dupliverts i.stack.imgur.com/STZqQ.png (quick explanation: blender.stackexchange.com/a/15997/15140) on a Circle mesh with Rotation option enabled and then ran the "make duplicates real" operator to "bake" the duplicates in the scene. If you need further explanations, feel free to write again or ask a question in the site: maybe someone else use other techniques. – Carlo Nov 13 '18 at 20:30
• Very grateful, Carlo, than you. I'll read up and check it out. It's slow - but FUN! – VectorVictor Nov 13 '18 at 21:17