Incomplete part update when sketch pattern count changes

[cadull_rb]

The attached part, created in Inventor 2012, has a formula for the number of occurances in a sketch pattern based on its length. When this number changes due to a length change, some parts of the sketch do not reposition and Inventor does not indicate that an update is required. The part can be fixed by dragging the affected geometry or performing a rebuild all. The following image shows the result when the length changes from 300 to 500.

[PaulMunford]

I don't suggest that you use patterns in sketches for this very reason (amongst many!).

It is much more stable to pattern features in parts, or parts in assemblies.

Would you like to tell us a little more about your workflow, so that we can make some suggestions?

Paul

[cadull_rb]

Please see http://forums.autodesk.com/t5/Autodesk-Inventor/Best-workflow-for-structural-member-design/td-p/3377... for my follow up.

[cean_au]

learnt to use ceil from here.

After change the Length, I tried put = in front of ceil(length/100) and press Enter, the drawing is fine then.

through don't know it was not right at the first place.

[PaulMunford]

Have you tried the frame generator?

[PaulMunford]

This may be a units issue. Check your document units against the units you inputted and the units you actually want.

Don't forget that 100mm is not the same as 100ul. Some parameter require avalue in ul. If you feed in a value that is in mm, Inches or anything elese you won't get the value you were looking for.

Check out the isolate function as well:

isolate(expr;unit;unit)

http://beinginventive.typepad.com/being-inventive/2011/11/using-isolate-in-parameter-equations.html

http://wikihelp.autodesk.com/Inventor/enu/2012/Help/0073-Autodesk73/0733-Design_O733/Functions%2c_pr...

[cadull_rb]

It has been a while since I tried frame generator (using Inventor 2011). At the time I found the workflow to be fairly slow, positioning the structural members on alternate sides of a sketch so they overlap back to back and offsetting the ends to complete the lap or allow for a bracket. I also had trouble updating the component in content centre without breaking existing usage. The way frame generator handles end offsets also added complexity for our addin to handle hole punching.