Better equation management tools?

Jun 25, 2008 4 Replies

Just ran into a problem. Trying to use equations to parametrically drive a number of fins on a design. A master fin is patterned. The idea was to drive the fin count and spacing with formulas and then use various configurations to play with different options.



It's a simple matter to connect the pattern count to an equation. It's also simple to then use this count and the available length to figure out the resulting fin spacing.



The problem is that you can't change these as you add configurations to the part. All you can do is suppress or un-suppress equations.



So...you would have to have ten different "fin count" equations, each one activated by the corresponding configuration.



OK, so, maybe you can deal with this...a bit of a pain, but maybe not so bad.



The problem comes in when you decide to add a couple of new configs after you've set all of this up. What happens is that equations are evaluated in the order they were entered, so a "fin count" equation that comes after the "fin spacing" calculation equation is not seen by the calc. When you suppress all prior "fin count" equations and enable the new one, all prior calculations based on the new "fin count" equation fail.



What's needed is a way to be able to move equations up and down in the list.



Or, better yet, to be able to create equations that have the ability to have different values assigned on a configuration-by-configuration basis.



Any ideas?


-Martin


A couple things:

  1. Always use a design table to regulate config-specific equations. Otherwise, suppression states can be unstable.

  1. Perhaps you don't need to have your "master" equation be config- specific. Perhaps just one or two of the parameters can be config- specific.

  2. Sounds like you could come up with a single generic equation that would work for all configs, if you're willing to do enough algebra and careful typing.

  1. You can cut-paste to rearrange equation order under "Edit All".

Use a design table?

Bob

How about creating sketch with dimensioned line and having dimension value controlling your pattern qty, using equation or design tables this will work with configurations

Just an idea I have use somewhere, sometime ago.

controlling your pattern qty, using equation

This is a good cheat 'cause you can't drive equations from a design table. Not what I would consider "elegant" but probably do-able as long as you name the sketch something sensible and add a note to let others know why you have this sketch that doesn't seem to do anything.

-Martin

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