Rob Edwards

Combining Variable Pattern and Equations

Discussion created by Rob Edwards on Oct 12, 2018
Latest reply on Oct 13, 2018 by ömür tokman

Hi All


I don't use variable patterns very often, I've only really tinkered.

But today I had to model a part that I've done before, but I've never been happy with and I thought I'd give a variable pattern a run out.

I was delighted when I saw that it added all the dimensions into equations...

..  hopefully now I could control this tricky little fella




This part is not really for production drawings, it's just meant to be indicative of what it might look like.


It's a series half lapped boards, which are tapered and roughly decrease in width from the bottom to the top.

All my previous attempts required a lot of manual adjustment so I'm quite pleased with this one.


I discovered a few interesting things.


Generating random numbers in equations is a bit crazy.  Say you have a global variable = RND(),, well every time you use it you get a different value.

To overcome this I created sketch points using RND, and froze the sketch.  I then used driven dimensions in a subsequent sketch to capture these.

Even when the sketch is frozen, the equations keep randomly mutating,,, it's a bit weird.


To get a reducing width as we go up the door, I had to use triangular numbers, which took a while to wrap my head around.




On top of the reducing width, we also have a random taper.

To make sure that we don't end up with the leaning tower of pisa, the model orientates each board so as to be level(ish) as we proceed



It was a lot of fun.  However at the moment it's just good for a fixed number of boards.

Maybe I can configure it and use a Design Table to modify all the equations, but I reckon any enjoyment will be short lived if I start down that route.


Anyway it's hometime..  My conclusions I think combining a variable pattern with equations makes for a powerful combo




2016 attached