Inequality & modulus constraints?

brooks_talley

Is there any way to create sketch constraints that reflect "greater than / less than" or "is a multiple of"?

Two scenarios:

• I have two holes that need to be at least 1" apart. They can be farther apart, but they can't be closer. 
• A spacer can be any multiple of 0.5", but making a 1.3172" spacer is prohibitive

Right now I'm just getting the sketch close and then eyeballing and adding a fixed dimension. Seems like it would be cleaner and more future proof to have OnShape solve for those.

mahir

There is no boundary constraint in OS, and I haven't seen anything like that in any other CAD software either. However, you can definitely use variables to drive your dimensions, and those variables can be the result of fairly complex branching logic. For example, you can make your hole spacing dependent on a variable that controls your panel width. In this example if #panel_width is less than 2in, then your hole spacing will be 1in. But if it's greater than 2in, then the hole spacing will be the panel width less 1in.

#hole_spacing = #panel_width < 2? 1in : #panel_width - 1in

As for the spacer example, you can definitely use expressions for that, too. This expression will set #spacer_width to #x rounded up to the nearest half inch.

#spacer_width = ceil(#x / 0.5in) * 0.5in

mahir

Check out the Measure Value FeatureScript. I believe it does exactly that. Alternatively, you can create the variable first and drive the dimension with the variable.

mahir

There is no boundary constraint in OS, and I haven't seen anything like that in any other CAD software either. However, you can definitely use variables to drive your dimensions, and those variables can be the result of fairly complex branching logic. For example, you can make your hole spacing dependent on a variable that controls your panel width. In this example if #panel_width is less than 2in, then your hole spacing will be 1in. But if it's greater than 2in, then the hole spacing will be the panel width less 1in.

#hole_spacing = #panel_width < 2? 1in : #panel_width - 1in

As for the spacer example, you can definitely use expressions for that, too. This expression will set #spacer_width to #x rounded up to the nearest half inch.

#spacer_width = ceil(#x / 0.5in) * 0.5in

brooks_talley

Very nice! Both of those are super useful. Is there a way to define a variable from a driven dimension? In the second example, if I could just define #x as the measured distance between two lines, I'd be in business.

mahir

Check out the Measure Value FeatureScript. I believe it does exactly that. Alternatively, you can create the variable first and drive the dimension with the variable.

brooks_talley

Fantastic -- those pieces assemble to exactly what I need. Thanks!

mahir

No problem.