driving dims and top down design

[tdx99]

Hi All,


We are looking to move to a top down design approach and have some questions about showing driving dimensions on drawings. We are currentlyshow driving dimensions to fully detail parts. With top down design, if the parts are driven by the skeleton, is it still possible to show driving dims on drawings? How do you guys handle top down design and showing driving dimensions?


Thank you.

 

[dgs]

No, the driving dims are in the skeleton and cannot be shown at the part level.

However, those skeleton dims are not likely relevent to your part. For example, perhaps a shaft position needs to be held a certain dimension from another shaft in the assembly. But, those two shafts don't pass through a common part. The skeleton dimension that describes your design intent would have dimensions out in space on each part for those shaft positions, but that's exactly the dimension you want in your skeleton.

The answer is either to let go of the requirement to only show dimensions, or not to use skeleton driven TDD. Personally, I've found the benefits of only using shown dims to be minimal at best and the benefits of TDD are enormous.