5 Replies Latest reply on Apr 30, 2012 1:54 PM by Jerry Steiger

    Using variable (global or local) in equation driven curves

    Philippe Vallee

      Hi all,

       

      I'm trying to draw an equation driven curve that would use global or local variable. SW 12 documentation clearly state :

      "You cannot use global variables directly for equation driven curves. However, you can create a global variable and associate it with a dimension, then use the dimension in the equation for the curve."

       

      This is a serious limitation. Variables can be either positive or negative but dimensions in general can't (?). Variable can be really small like 1e-9. Dimensions can't.

       

      So my question is : Is there a work around ?

       

      If not, how do I complain to Solidworks so they fix that problem ?

       

      Finally, I found that, in the equation driven curve editor, number likes 1.2E-6 is not understood correctly by solidworks. One must write 1.2*10^(-6).

       

      Anyone ever noted that ?

       

      How do I report that ?

       

      Thanks

       

      Philippe

      P.S. Below, an example of the kind of equation I want to drive with variables. This is for the sag of an asphere lens. I want to replace numbers like -8.5995732*10^(-9) by a variable. So when the design of the lens changes, I don't have to dig the number. I will just need to edit the table of global variables.D3@ESQUISSE1 is the radius of curvature of the lens which is a big number and is a readily available dimension so I can use it.

       

      -1*(((1/"D3@ESQUISSE1")*(x^2))/(1+sqrt(1-x^2/("D3@ESQUISSE1"^2)))-8.5995732*10^(-9)*x^4+7.8575671*10^(-14)*x^6-8.3052033*10^(-19)*x^8)