
Cut and Fill Calc's on form•Z Cut and fill calculations can be a very long and tedious task in any profession. So I have taken the liberty to discover an easier way to accomplish this daunting task. This page will help demonstrate my work with form•Z and how it makes cut and fill calc's a snap. The Process This project came about after I had been working with form•Z terrain models in one class (Arch481) while also doing cut and fill calc's in a landscape construction class. In our construction class we learned how to calculate cut and fill using a large grid format along with a formula to calculate change in grade per grid cell. This method was very long, boring and filled with numerous mistakes. So I set out to find an easier way to calculate cut and fill. This page is a look at how form•Z cut and fill calculations compare with those done by hand. Feel free to download the DXF contour files and try this yourself. I'd appreciate it if you'd email me with your results Beginning with a Site Plan
The first step in calculating cut and fill in form•Z, is to take site contours and scan them into the program. Below are the existing and proposed contours from the site shown above.
Creating Terrain Model Once you have the contours traced into form•Z, you can then create a stepped model of each group of contour lines. This is done by using the Terrain modeling tool in the program. You select the type of model (I used a step model), then you adjust the contour intervals and starting height, then select the contour lines in ascending order and then you have a 3D step model of your site!!! Below are the steped models fro the existing and proposed contours of my project site.
Comparing Cubic Footage Once you have the two terrain models (existing and proposed), you can do a query on each of them to see the cubic footage of each model.
Final Cut and Fill Calculation Once you have these numbers, you subtract the proposed number from the existing number to get a total change in cubic footage. This number is used to calculate cut and fill just like the hand done calculation were, meaning that a negative number means overall cut, and a posative number means overall fill. Here are my numbers:
Final Conclusions Well there you have form•Z's final cut and fill Calculation, but how does it compare to those done by hand. Well lets look at what I came up with:Final results per Method
As you can see the numbers are very close. But the real key here is the amount of time it took to do each set of calculations. Lets compare those: Time to calculate per Method
The bottom line here is that form•Z can can calculate precise cut and fill calculations in about a third of the time it takes to do the same calculations by hand (if you never make simple mathmatical errors I mind you). Therefore I can honestly say that form•Z is a quicker more accurate way of calculating cut and fill, and should be used more readily to save time and money on this annoying task. But, cut and fill is not all form•Z is good for, check out my other pages to see what other aspects of landscape architecture form•Z is a more efficient tool. Chad Whichers, 1998 