topic Re: Creating near vertical as-built surfaces in Civil 3D Forum

Creating near vertical as-built surfaces

Shea_G — Thu, 21 Oct 2021 13:57:01 GMT

Hello, I was hoping to get some ideas on how other people would have fulfilled a recent request...

A client wanted to compare a near vertical concrete wall that was poured incorrectly vs design. I setup a robot and gave it a rough scan every 0.2m, brought the point data into Excel and created a delta distance off design for every point along with chainage and elevation from top of wall for each point. Paired with a plan view of the wall showing chainage and point nodes on the wall.

The problem is it's a massive table and not easy to visualize. I would have much prefered to make a volume surface using as-built vs design and used elevation banding to show deviation. Which would have been great if it were a horizontal surface like the floor. But c3d doesn't handle vertical surface as well.

What would you have done?

Re: Creating near vertical as-built surfaces

tcorey — Thu, 21 Oct 2021 14:11:30 GMT

I would survey points along the bottom of the wall and the top of the wall, and then create Feature Lines through the points. Use the Feature Lines as Breaklines in the Finished Wall surface. If there are any places where the wall is actually vertical, you can move Feature Line points manually, eliminating any verticality. Once you've done that, you can create a TIN Volume Surface to compare design vs. finished.

Re: Creating near vertical as-built surfaces

Shea_G — Thu, 21 Oct 2021 14:27:25 GMT

That would have worked if that level of detail was acceptable. The form broke and the wall has a big bulge in it. The 0.2m x 0.2m point density was as coarse as I could have given.

Re: Creating near vertical as-built surfaces

tcorey — Thu, 21 Oct 2021 14:38:20 GMT

You can rotate the points 90 deg in relation to x or y axis. Now Plan View is like looking at the wall from the Front. Points will not be above or below each other, so no verticality will exist.

Re: Creating near vertical as-built surfaces

Shea_G — Thu, 21 Oct 2021 14:49:41 GMT

I was thinking of this. I just cant figure out how to do it.

Re: Creating near vertical as-built surfaces

fcernst — Thu, 21 Oct 2021 15:17:12 GMT

When you talk about wanting to do a volumetric analysis.. and the bulge.. it sounds like the rock overhang scenario that the Help shows how to model using the subcriteria workflow.

Re: Creating near vertical as-built surfaces

Udo_Huebner — Thu, 21 Oct 2021 15:19:55 GMT

I did this years ago the same way @tcorey suggested. A ship's side was deformed in an accident and needed to be compared to the original design.

I imported the measured points X,Y,Z as X,Z,Y and the ship was rotated 90° about the X axis on screen.

Worked like a charm.

Re: Creating near vertical as-built surfaces

Shea_G — Thu, 21 Oct 2021 15:55:47 GMT

Thanks for all the help. I swapped the northings with the elevations and created a design surface setting the elevation at the design northing. Worked like a charm.