Top Down Design With Solidworks 1

[JGard1985]

Hi all

I'm using solidworks for top down design (basically using layout sketch to project parts and extrude). I'm being challenged because my parts are jumping from the projection of the layout sketch to random regions. Solidworks says that the part is still confined but i cant figure out where solidworks is getting messed up

I can see my assmebly load correctly but then jumps to an offset as the loading is complete.

Anybody experianced anything like this before?

Thanks
Jeff



Jeff
Pipe Stress Analysis
Finite Element Analysis

http://www.xceed-eng.com

 

[SBaugh]

Of course, what you are seeing is the result of In-contexting (Top Down). I highly doubt its random, I am sure you have something confined to something else that is causing the issue. In-contexting can be done in both the sketch and the feature processes. If your not sure what you have done, then i recommend getting rid of all External references. This can be accomplished in the Part Sketches, then by using the "Display\Delete Relations" and remove all the external references. If you were in the assembly and selected faces to extrude up to then you will need to change that to blind dimension to remove the relationship.

In-contexting is not a beginner feature and takes time to feel it out. I always watch for the ">" symbol in my files, features, and sketches so I know there is a relationship. However after the design is complete I always remove my relationships.

Scott Baugh, CSWP
CAD Systems Manager
Evapar

http://www.evapar.com

"If it's not broke, Don't fix it!"

faq731-376

 

[TheTick]

Usually in top-down design, I start with a master sketch, just as you did.

My next step is to copy the master sketch into each component that is using the top-levelmaster sketch as context. The master sketch creates sub-master sketches, but is not used for anything else. This results in much more stability. Also much easier to fix when design changes cause issues.

Make sure all your components are fully constrained or fixed. Most of my designs components are fixed with common origins.

 

[drawoh]

JGard1985,

In-context modeling is the least idiot resistant feature of SolidWorks. You cannot just apply parametric features and expect things to not blow up. Model and mount your parts from a stable, not-in-context base. Anticipate how your part will update when you change stuff. Avoid complex sketches, especially on your base features. These blow up completely.

--
JHG

 

[SBaugh]

I think if your careful when doing incontexting it works great. When you start getting lose with your constraints is when people start seeing problems. I have made completely automated assemblies using top down design and rarely did I have problems with it. The reason is because I was meticulous with how I organized and placed my relationships.

Scott Baugh, CSWP
CAD Systems Manager
Evapar

http://www.evapar.com

"If it's not broke, Don't fix it!"

faq731-376