reanimator-solidworks.jpgAssemblies people! Not assemblies of people, which can have you going through more gallons of fake blood than a remake of the Re-animator, but assemblies of inanimate chunks of 3D data.

You can make really, grossly huge assemblies but there’s a point where people start whispering about you behind your back. Instead of spending your morning talking gossip with the office manager while your models load, split them suckers up and do a little dance that will also have people talking behind your back.

Four Reason to Hack up Assemblies
There are 4 reasons why you would want to start choppin’ up a fine mass of plastic, steel and screws and it’s all about small. Small stuff that makes a big difference. Now isn’t that clever?

  • smaller file sizes
  • smaller BOMs (Bill of Materials)
  • smaller drawings
  • smaller FeatureManager mess

Building these four ideas into your methodology alone can help keep your assemblies in a more manageable state. Dwell upon them, stare at the ceiling repeating them in a low monotonous voice and then also use these four techniques to split them up.

1. Combine parts that don’t attach together
Can you see the possibilities opening up already? A group of connected parts that attach to another group of connected parts is typically how we think of sub-assemblies.

Thats a fine approach to creating assemblies, but remember as you read the rest that any part or assembly can go into another assembly.

2. Create yourself some sub-assemblies
Phenomenal concept, hem? Well, you’ve got everything in the assembly to the point it’s overwhelming you and your computer. Considering what to put into sub-assemblies is the first step. Here’s four possible solutions.

  • Parts that are manufactured in the same place
  • Parts that are or could be put into kits
  • Raw material parts only
  • Hardware only

Once you’ve thought that over, you can go to your FeatureManager, find the items you want to combine, hold the Ctrl button while selecting them, then right-click and select Form New Sub-Assembly.

3. Dragin-n-Dropin-n-Dragin
Yes, so obvious, using the mouse to move items into and out of assemblies. Simple, yes, but don’t be afraid to do it. After you’ve formed some sub-assemblies and created some drawing views, you may decide something would have been better off in another location.

To get an item out of a sub-assembly and into the top assembly, drag it to the very top line in your FeatureManager. If you already know where you want to put it, drag it straight into the other sub-assembly. It’s something pretty basic, but not all that comfortable to do until you’re use to it.

4. Optimizing your drawing
You most likely have a standard for your drawing layouts. It would be great if everything could fit on one sheet, but sometimes models need a little bit more detail. Here’s a few questions I ask when harping on making drawings more simple.

  • Can those 4 drawing views be reduced to one exploded isometric view?
  • Is all of the detail needed or can I show some sub-assemblies as reference?
  • If it’s not providing any value is it needed?

After checking a drawing and asking this, I’ll see what I can eliminate and how I can combine parts into -subassemblies to get a better looking drawing.

A note on top-down design
SolidWorks 2007 and 2008 are pretty good at keeping relations when moving parts around. SolidWorks2008 gets rid of the annoying “This part has features defined in the context of another assembly…” warning. So, if you work in large context driven assemblies moving to SolidWorks 2008 can save you a lot of pain of dealing with contextual relations. Rockin’.

Are there better ways to create a drawing or assembly or part? I think it’s something we need to ask every time we start something new.


Josh is founder and editor at, founder at Aimsift Inc., and co-founder of EvD Media. He is involved in engineering, design, visualization, the technology making it happen, and the content developed around it. He is a SolidWorks Certified Professional and excels at falling awkwardly.