It is nice to come from behind the coding page and peek at some of the new features of C3D 2009. One of the new features that caught my eye was being able to set design criteria. What is it and how can it help you?
Design Criteria File
The design criteria file is simply the same XML file that has always been there and was used for setting superelevations using the wizard. However, now you can use this to verify that your radii are big enough for your design speed (among other things) and even tweak the criteria using the Design Criteria Editor.
Design Check Sets
What if the design criteria does not cover all the aspects of the design you need to check?
Enter the design check set.
A design check set is a collection of formulas (created similar to expressions) that are also checked with your design. For example, you know that to get all your superelevation transitions in from one curve to another curve, you would need a minimum of 500 feet on a road that has a design speed of 70/mph. You would create a design check to make sure your tangent length would be greater than 500 feet if that tangent fell into an area where the design speed was 70/mph.
Whew! That seems like a lot of work but it is not hard to setup and is much easier than checking it all by hand. (TRUST ME)
Design Criteria/Check Violations
The nice thing is if your design criteria and/or checks are violated it will STILL let you do the design. It will simply flag that portion that is violating the rules with a big exclamation point.