Changing designs and sketches in SolidWorks

Do you think EVERY/ALL designs can be adjusted automatically in SolidWorks by changing dimensions (a few inches) in a main sketch on top of the design tree no matter the complexity? So every feature under it (say 10-15+ or more with surfaces) would adjust accordingly. I’m not sure but I’m guessing not every single feature can be changed automatically by 1 sketch in every design. It may work in most but not all is what I believe but I could be wrong. What do you think?
…and I’m talking finished engineered designs with bosses and ribs etc!

Yes… and No. It all depends on the specifics of the design, and how you’ve built your parts. If you’re changing an overall dimension, you certainly can. You could even build a Design Table, and have multiple configurations of your parts…

when can you not change a design dimensionally right at the stage of prototyping. Can you elaborate and give an example on when you are not able to modify?

and when you say multiple configurations do you mean display state?

If you make your parts and define your dimensions with future revisions in mind, it’s absolutely possible, regardless of complexity. The effort invested in CADding in this manner, however, may or may not exceed the effort required to manually “repair” a part/assembly for which a simple rollback didn’t work.

I generally don’t worry about it. I’ve cursed my folly on occasion, but not often enough to be as rigorous with constraints/dimensioning as I’d need to be.

-Josh

THX Josh. You sound very experienced. How often do you have to start from the top again to make revisions than just changing a number and make your whole project adjust? I guess it also depends how fussy and indecisive your boss is too!

It’s kind of hard to give an example, but the one used in the SW tutorials is this:

Think of a socket wrench. Your initial design calls for a 6" long handle that is 1/2" diameter. You decide that that isn’t going to work, but a 6.5" handle 3/8" dia is perfect. If you build your sketch with revisions in mind, you should be able to change those two dimensions and update the part and be in business.

Look up Design Table in SW help, for more info on multiple configurations (I don’t mean display states. I mean actual variations of the same part, as listed above)

THX Nurb

I’d say once out of every twenty components I draw, there’s some fundamental problem with the original extrusion that I can’t backtrack and fix quickly in a rollback state, or kludge into the proper shape with a wonky additional cut/extrude that doesn’t make a whole lot of sense from a manufacturing standpoint. I generally have to change it to the appropriate shape, then work through every feature I’ve done and redefine where all the constraints are WRT the new shape.

I’m not a CAD master by any means; there may be some SW-jitsu that would make it substantially easier to do the single-rollback-dimension-alteration, and if I were doing substantially more complex parts I’d definitely invest the energy in it, but for the basic stuff that I use it for, an occasional manual alteration is fine.

-Josh

Yes this is very possible. You need to be working with equations in solidworks where all the features are related to the very first sketch you built. Design tables will also work. I find equations a little easier to work with.

depends on part complexity too. I find using good sketch relations relative to existing geometry vs dimensioning off the origin can help a lot…

Its all about proper modeling. By adopting the right modeling method, you can create intelligent models that are highly variable. That is the basis of parametric generative design. To embed design intelligence into the CAD model. But a lot of designers are only focused on the final outcome. So they do not give much attention to how to model property. If you keep variability in mind from the beginning then you are likely to create models that are highly variable.

There are two distinct ways of working in SW (or most other parametric programs) as alluded to above:

  1. Build it quick, fix it again, make a big messy feature tree and don’t bother with the notion of “right”.
  2. Plan, plan, plan, try to build it right at the beginning. Inevitably, Marketing steps in and screws you up anyway! :laughing:

Building a model so it regens 75% of the time is good enough for me. I like the classical beauty of having an intelligent model that is easily tweakable, but when you’re talking about dozens of surfaces, curvature continuity, solid/surface functions…its not going to regen every time. Plus, I use SW as an iteration/visualization tool, to try to ‘see’ what something will look like, and then build on that, etc. So its often not possible to ‘predict’ these things at the first feature.