Advanced Daylighting Design and a farewell...

Hi all - this design scenario came up a few weeks ago, funny enough from two different sources, in Europe and North America.  How do you design an Assembly that in cut conditions daylights from the hinge point and has two parts (see below); first a variable dimension (x) and then a second part with a fixed dimension (y)?  As you may know, at first glance Assemblies can only have a variable dimension on the "last" daylight portion, where you just tell the Subassembly to find the surface wherever it is.  This seems impossible - how could we achieve this?

  

To understand the solution we will quickly review the definition of a parallelogram.  It is a rectangle in which the opposing sides have equal length, like this:

  

Look at the X and Y portions in the first graphic and compare - any ideas?  We DO need to start with a fixed variable and end with a link to find the surface, but here's another hint - you can create Links as construction items and use the "Omit Link" property.  Stumped?  Let's take the design criteria and combine it with the parallelogram concept to get a solution!

Part 1 

1. Use a LinkWidthAndSlope to create a fixed daylight offset
2. Then add a LinkSlopeToSurface

This is exactly opposite of what we want, right?  On to Part 2...

  

Part 2 - now we are going to go "backwards" to get the links we actually want. 

1. From the daylight point at the surface, create the same LinkWidthAndSlope, but in the opposite direction
2. Then add a MarkedPoint to the end (give it a name when creating)
3. Now from the original hinge point, attach a LinkToMarkedPoint and provide the MarkedPoint name

  

See what you have done, you have created a parallelogram!  Now you need to go back to the two subassemblies you created in Part 1, right-click and Edit Subassembly.  In the Subassembly Properties, just turn the "Omit Link" property to "Yes."  Now those subassemblies are just construction pieces and will not be drawn when you create your corridor.  Perhaps now your horizons have opened up to other possibilities - my thanks to Tomas Lendvorsky, Autodesk's Solutions Engineer from Prague (he's a whiz with Expressions too!).

  

A farewell: this will be my last post on the BeingCivil blog, as I have accepted the position of Social Media Manager in Product Support.  I would like to thank you all for joining us here on the BeingCivil blog, following us on Twitter and YouTube.  BeingCivil lives on, with the critical support of our other great authors: Almas, Jason, Justin and Seth.  My congratulations as well to Joshua Coombs, who takes over as the Technical Lead for Civil in Product Support.  I wish you all success and happiness in the coming holiday season and beyond, and finally, don't forget to "Be Civil"!