The question on how to create surfaces from contours has come up lately and decided to create a write up. More than a how-to, I wanted to get into more details on the options when minimizing flat areas.
Surface from Contours
First, the contours MUST have elevations assigned to them. Typically files that come only have contour data provided have NO Civil 3D set up and styles. Optimally as the workflow should be to:
- Start by creating a new drawing using a Drawing Template that has a Civil 3D set up (preferably yours).
- Insert the drawing that has the contours and explode it.
- Create a new Civil 3D TIN surface (from Prospector or Ribbon).
- Set values in Create Surface dialog box.
- In Prospector, expand + the surface > expand + Definition
- Right click on Contours > select Add… > s
- Set values in Add Contour Data dialog box.
- Select Contours lines (preferably all other layers have been turn off)
Surfaces are great, as soon as x y z values are added, a surface is created.
Minimize Flat Areas Options
The above functionality has been part of the software for quite a long time now. What I wanted this post to add is more detail on #7 above, and show is the different surfaces created using the different combinations of the Minimize flat area options.
To test, multiple surfaces were created with different combinations. To compare the results surface a profile view with all the profiles were created. The default choices creates the surface that stands out in green below. All the other surface combinations create profiles that line up on top of each other.
The difference can also be seen in PLAN. Again the default choice creates contours that stands out in green below. All the other surface combinations create contours that line up on top of each other.
Having experimented with the settings, I am now leaning towards the surface generated using the first 3 check boxes.