"shown" dimensions and TDD skeletons

[mloew]

Gurus,

Does anybody have any tips on how to efficiently combine a desire to use "shown" dimensions on drawings with the rigorous use of skeletons (as parts, not the DM skeleton) and Top-Down Design? These methodologies seem to be at odds with one another. I am using skeletons to maintain all of the design intent and interfaces of major systems. The components that make up the systems are controlled by using external references of published geometry features in the skeleton. What I am finding is that most, if not all, of the dimensions are controlled in the skeleton parts not the component parts and assemblies. This is a good thing until I go to have a drawing made: There are no dimensions that can be shown; all dimensions must be "created" in the drawing mode. I share my company's desire to restrict the use of created dimensions, as it is typically poor form.

Is there any way to use reference dimension to fully detail a drawing? I need to have toleranced dimensions, GD&T, etc.

Any help would be appreciated.

Best regards,

Matthew Ian Loew

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Hayden]

In your sketches you can create reference dimensions the same way as driving dimensions. These can then be shown in drawing mode. They'll all show ref after them though so you'll need to edit his out.
If you're going to do that though why not just create them in drawing mode? Two steps versus one. Also basically what you'd be doing is creating dimensions in your model rather than the drawing. Is it because drawing created dimensions can be deleted accidentially that you're not keen on them? I've always struggled to understand why created dims are see as so evil, especially in instances like this.

 

[looslib]

The Pro/E mentality is that only shown dimensions are actually connected to the model, since the software 'generates' them for you, showing design intent. Created dimensions are driving from the user picking end points and therefore the wrong point could be choosen in a tight area.

An area of more concern would be those who model a part from one end and then dimension it from the other end.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand