I spent the day going over my PCB design, and am beginning to feel more confident about it. As part of this exercise I played around with KiCad's 3D modelling feature. I have to say I'm very impressed.

The KiCad library of generic 3D parts it pretty good, but I still had to search around a bit for models with a closer match to the components I will be using, especially in my case the push button switches. Fortunately it's relatively easy to modify the footprint libraries to use these found 3D models. Very cool.

Aside from looking cool how does this help me? Well it turns out that this 3D model can be exported from KiCad as a .step file.  This in turn can be imported into Fusion 360. How does this help? Lets see.

When I popped one of my 7-segment displays and a push button into a project board, I noticed that I had gotten a bit lucky with my choices.

The push button is about a millimeter or two taller than the 7-segment display. This is perfect for my purposes because I want the membrane to lay on top of all the buttons, LEDs, and displays. Being slightly taller will allow the button to be more easily pressed. 

In order to better support the membrane I will be printing a standoff with cutouts for the displays, LEDs, and buttons. By measuring the height of the 7-segment display relative to the PCB I know that this standoff needs to be 9 mm tall.

Before I have even sent the PCB design to the fabricator, I can validate that the standoff cutouts are correct by bringing the 3D PCB model into Fusion 360 and aligning it with the standoff.

Now the 3D button model of the switch that I found for the PCB is actually a little taller than the actual, so it protrudes in the image above more that it will in practice, but the switch cap is correctly sized at 12 mm x 12 mm, so I can see that the alignment of the cutouts appear to be accurate.  Nice.