Equation Puzzle

Log on to the SW discussion forum and go to Parts. Find the topic with
the same name as this thread. Download the part and remove the first
equation. Then rebuild a few times. How does this happen? Should this
happen? Does it violate any SW rules?

If you want to get the part back to the starting point put the first
equation back in momentarily.

 

Can't believe nobody has given this a shot.

 

I replied to your post at http://forum.solidworks.com/swforum/
yesterday morning. Take a look and tell me if it sounds right.

Ken

 

I wouldn't exactly call it a circular reference, but it shows that you
can define a part early in the feature tree by a dimension later on in
the feature tree violating the Parent / Child (Chicken and Egg) rule
that parents should define the children and not vice versa. The reason
is that equations are evaluated prior to features being evaluated.

This error in the part was intentional as it is only a warning and is
necessary to get the part to shrink back to a manageable size.

Would you agree that trouble shooting a model with this kind of
arrangement in it would present some difficulty to the average user?

 

violating the Parent / Child (Chicken and Egg) rule
<<<
I didn't realize that this was the point of the example. Yes it looks
like you are correct.
Would you agree that trouble shooting a model with this kind of
arrangement in it would present some difficulty to the average user?
<<<

Yes. Definitely. Personally, I (intentionally) try to never use
equations. First I try to create a relationship to other geometry. If
that doesn't work then I would use a Design Table. I find Design Tables
to be easier to write/debug, and easier for me or someone else to reuse
and understand later (compared to using equations). I don't really
understand how you would use this method to troubleshoot, but most of
my models are simple prismatic or cylindrical parts that usually don't
require *any* equation driven relationship. My part Feature Tree is
rarely more than half my screen height. Maybe there is a benefit/use of
this troubleshooting method for more complex parts (but I would still
look to Design Tables first)?

Ken