General How To

How can I pivot a lens group around any points in space?


Coordinate Break surface is an important tool in Sequential mode for placing surfaces/elements at any position and orientation in 3D space. When tilting a surface in Sequential mode, by default the pivot point is at surface vertex, and when tilting an element consisting of multiple surfaces, the default pivot point is at the first surface vertex.  

 

 

However, depending on the mounting arrangement sometimes it’s necessary to set up surface or element tilt pivoting around other points, for example the top or bottom edge of the element, or around a random point in space. We have a Knowledgebase article introducing the step by step process at How to pivot any element about any point in space – Knowledgebase (zemax.com). As you can see this process can get quite complicated.

To help ease this effort, now the Tilt/Decenter Element tool has been extended to support pivoting around any point in space. Users first highlight the range of surfaces they would like to tilt as a group, then click the Tilt/Decenter Element tool in the tool section of the Lens Data Editor, highlighted in red circle below. There they specify the pivot point using its coordinates x, y, z, in either local or global coordinate system. In this example below, I have used local coordinate system and (0,-10,3) sets the pivot point to the bottom edge of the back face of the glass window.

 

 

After setting this up, you can run a quick test to confirm if the pivot point has been set up properly by adding a second configuration to make this a multiple configuration system. In MC editor, use operand PRAM to introduce a 30 deg Tilt X angle to the second configuration while no tilt is done in the first configuration. Last, in the 3D Layout window choose “Color Rays by Config #” and Show “All” configurations. Now in the Layout window the two configurations will be displayed simultaneously. This overlay provides a clear visual as to where the pivot point is and in this case it’s at the back face bottom edge as we have intended.