So, you want to add a circular tank to your surface?

Recently, we had a customer who wanted to add a circular (or I guess I should say cylindrical) tank to the site. Unfortunately, when the tank was added to the surface, the contour line was not very smooth.

As you can see, the red contour line is connected to a vertex of the base of the tank approximately every 30ft or so and, in places, as far as 1 foot away. This is unacceptable. We need to get this contour looking a little more like a circle.

The contour was originally added using the default values (see below):

Let's remove that contour from the definition of the surface:

And add it again:

We need to adjust the supplementing factor. I think most of us have seen and maybe even adjusted the Weeding and Supplementing Distance factors. The problem here, is that the distance values only apply to straight lines, not arcs or curves. For this circular tank, we need to adjust the mid-ordinate distance. See below:

To further explain what the mid-ordinate distance is, I have included this screenshot straight from the Help menu. Once we make that small change, here is what we end up with (I left the dimensions for reference):

MUCH BETTER!! Whoo Hoo!

I just received an email from Rod Sherry of Cullen-Sherry & Associates. He sent me a fantastic jpg he created from Civil 3D of their tank site.

Nicely done, Rod!