Just a variation to the original question. I've got my .ipt updating diag length and quantity based on ladder length. However is ther anyway of making sure the diag quantity is always an even number?
you could try using functions such as dividing by 2, rounding then x 2
Autodesk Product Design Suit 2012
Win 7 Enterprise 64bit
Intel core i7 2600K Clocked @ 4.7GHz
Nvidia GTX 580