Parametric Dimensioning

[D3sign3r]

Ok hopefully sw can for sure do this.
If im detailing a simple recangle plate, in sw2003, and i place a hole in the center, how do i specify that that hole will always be in the center of the width of the plate? Even when i want to change the width dimension later on? The Dimension modify box wont allow me to enter in the width name "D1", which i would like to specify "D1/2"...
thx.

 

[JNR]

I agree with the diagonal construction line/midpoint relationship method for some very specific reasons.

Obviously (for any CAD system) the least complex all definitions are the faster the system will run.

The more fundamental (simple) the definitions are the faster things will run.

You can't get much simpler than using basic trigonometric rules and principles. I always teach people that if you can define something simply via its basic geometry it is much better than adding lots of relationships and dimensions, etc later - they become time consuming and unnecessary.

Also the simpler things are, the easier they are to modify without unwanted effects occurring due to other interdependencies.

I appreciate the horizontal/vertical circle center-to-rectangle side and top midpoint relationship method (and similar ones). But it has a practical drawback in the general case. If you fillet the corners, or break an edge with some other feature in the sketch, this goes to pot real quick. Whereas with the diagonal contruction line, the "virtual sharp" intersection remains and your relationships stay put.

3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[TheTick]

That's why I prefer to do symmetry between edge pairs for this case. A construction line constrained symmetric to an edge pair is more robust and will not lose its reference if the corners are lost somehow. If you want the exact center, use two construction lines, one horizontal and one vertical.

All this machinery making modern music can still be open-hearted.