It was the most-requested SOLIDWORKS enhancement of all time: To be able to open files from a future version, or to be able to save files as a previous version. Since SOLIDWORKS ’96 users have asked for this and in SOLIDWORKS 2013 they delivered. And then it went away in 2015. And now in 2016 we’re Back to the Future!
What happened? And why is this so hard? I’ll tell you.
Difficult to see. Always in motion is the future.
– Master Yoda, Empire Strikes Back
Why Can’t We Save As Previous Version?
The number one thing to understand is that SOLIDWORKS data is complex and constantly evolving with each major release. This is not Microsoft Word or AutoCAD we’re talking about; this is a feature-based, parametric, 3D solid model… with associative parts, assemblies, and drawings. There’s a lot going on with this type of data, so it’s no trivial task to save it into a fully-functional format aligned with the capabilities of a prior, lesser version of the software. In fact it’s almost impossible.
It’s a bit like trying to take your iTunes library and save it as vinyl records, while also maintaining artist, album, and track information, including album art, and also how many stars you’ve rated each song. Oh, and you want to keep all your playlists intact too. On vinyl. To play on a turntable. Yeah right.
For example, SOLIDWORKS 2013 introduced a completely new sketch entity type for conic sections. So how on earth could you take a 2013 sketch, with Conics, and edit it in a previous version that has no Conics? The answer is, you’d have to strip out the parametric information, the user interface elements, the feature history, and get down to the very core of just the resulting solid model. In other words: Parasolid.
Save As Parasolid enables you to take any model from any version of SOLIDWORKS and open it in any other version of SOLIDWORKS. Or, for 2D data, we use DXF/DWG. And so it was for the lifetime of SOLIDWORKS. Then SOLIDWORKS 2013 changed all that.
Something Special Happened in 2012/2013
Really it was SOLIDWORKS 2012 SP5 that changed all that. That’s when the developers taught the software how to open files from the future! With Previous Release Interoperability, the final service pack of a release (typically SP5) is able to open files from the next release.
One fact that helped them achieve this is that ever since 2001 or so, there has been one extra Service Pack for the old release after the new release ships SP0. This means there’s an opportunity to put code into the old version that knows what the new version looks like, during the period that development of the two versions overlaps.
HENRY: You do understand why it is I don’t know you?
CLARE: Uh, of course. When you’re older, you’ll travel back to when I’m a little girl… I’ve known you since I was six years old.
– The Time Traveler’s Wife
We’re still bound by limitations of how much a Service Pack can alter SolidWorks while still remaining compatible within the same version! But it’s enough of an overlap that some functionality over future files can be realized. This also limits the interoperability to between consecutive versions only, for now.
So Can You Change The Future?
It turns out that looking forward or backward in time is a lot easier than traveling forward or backward in time. In general, we get read-only access to parts from the future, almost like working with Parasolid files, but it’s a little better than that.
|Parts From The Future
· Add to “old” Assembly
· Mate in “old” Assembly
|Assemblies From The Future
· Add to “old” Assembly
· Add more Components and Mates
You can Save the Assemblies from the future, with the old parts and mates in them, and you will see the changes when opened in that future release. You definitely can’t do that with a Parasolid export!
The major problem [encountered in time travel] is simply one of grammar…for instance, how to describe something that was about to happen to you in the past before you avoided it by time-jumping forward two days…
– Douglas Adams, Restaurant at the End of the Universe
The Oops of 2015
Ironically, a timing mistake in their enhancement planning schedule derailed the version interoperability for SOLIDWORKS 2015. The 2015 version of SOLIDWORKS implemented some file structure changes to improve performance and dramatically reduce file sizes. Unfortunately these changes were too significant to “teach” 2014 SP5 how to read.
If they had implemented the data structure changes sooner, or delayed the interoperability project, we wouldn’t have this gap in continuity. But it doesn’t really matter since that’s all in the past now. (Pun intended.)
The Future Is Back In SOLIDWORKS 2016
With the data structure settled after 2015, the interoperability has been reinstated between versions. Starting with SOLIDWORKS 2015 SP5, we can again open files from the future (in this case, SOLIDWORKS 2016). I don’t expect we’ll see another gap in this chart.
|This Version||Can Open This Version||?|
SOLIDWORKS 2015 SP5 was made available for Early Visibility download on 9/28/2015. I’m not sure when it will be officially released, because I cannot see the future…
Please, Marty, don’t tell me! … If I know too much about my own future I could endanger my own existence, just as you endangered yours!
– Doctor Emmett Brown to Marty McFly, Back to the Future