Redesigned crossheads refine OnShape technique

To be honest, I don’t know if I would have this much patience if the real workshop were not still out of commission.  The sheet metal design for the crosshead guides and crossheads took several days (well hours, as I don’t spend whole days on this stuff!) due to a disagreement between OnShape and me about how some sheet metal models should work.

We’ve finally agreed to compromise, and along the way, I’ve had substantial time to think about my OnShape technique.  One of my part studios contains some 347 features, and takes longer and longer to load each time I modify it, especially if I go back and update one of the foundation sketches.  Even worse, because I didn’t know what I was doing when I started creating this model, many of the features don’t even generate properly anymore!  All they do is drive the spinner longer, and give me more time to fume!

The key lesson from this process of going back and changing the way every part of the model was built is that you should not, as much as possible, refer to other parts when creating a part.  If you need to reference something outside the part that you’re drawing, reference a sketch.  This way, when you go back and change the reference part, your dependent part has a hope of not breaking.

This goes double for sketches!  I now think that most sketches should be on planes rather than on faces.  Indeed, the way I build the next complex OnShape model will be to start with a part studio that includes only the main elevations, plans and sections.  Then I will pull those sketches into other part studios to build the parts themselves.  Hopefully, by reducing the depth of the dependency tree, I can speed up model regeneration.

Well, I’ll let you know how it turns out.


2 thoughts on “Redesigned crossheads refine OnShape technique

  1. Rene, would you clarify the difference between sketching on planes and sketching on faces please?

    1. Sure – or at least I’ll try:

      OnShape calls a plane that is on the surface of a part a “face”. It also enables you to define an arbitrary plane that passes through any three points in space. These it calls “planes.”

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.