>>way to access data from an existing object (length, diameter, etc.).

Unfortunately no. I've been looking for a way to tie attributes to the constraint variables (like height of an extrusion).

>>I can't figure out what param really evaluates to.

Perhaps below will help.


There is also a param, const, and macro interface. In any numeric input field you can enter a new definition as follows:

@param=expression
This format creates a param value. The value of param is evaluated at the time it is created. It will not change value until a replacement is entered.

@const=#expression
This format creates a const value. The value of const is evaluated at the time it is created. Once created, a const cannot be replaced (unless you hand edit the prefs\UserMacros.ini file).

@macro=@expression
This format creates a macro value. The value of macro is evaluated each time it is referenced. Hence, its value can change over time as any param or const values are updated.

For example, in an input field enter:

@a=5// param a has the value 5.0
@B=#a*2// const B has the const value of 10.0
@M=@rnd(a)// macro M will be a random number between 0 and a

You can use a, B, or M anywhere the expression syntax allows a value!

So for a line's length you could now enter M+5 and the line's length would end up being some value between 5 and 10 (=5+a). If you then re-entered @a=10, and then entered M+5 as the line's length again, it would end up being some value between 5 and 15 (=5+a).

Tim,
Thank you. The information will be very handy. Its easier to remember (and enter) A1 than .06662 for instance.

E. Ham