topic Re: Point to surface comparison in Civil 3D Forum

Point to surface comparison

saeid_hajahmadi — Wed, 09 Jul 2025 01:53:59 GMT

I want to create a conformance report based on a set of points picked up and compare them to the design surface. I can edit the heights based on the design, export them, and compare them in an Excel file. I can then bring them back into the drawing with a new point group for my report. However, Civil 3D Tools has an option that creates a new point group for this automatically.

I wanted to know if there is a way in Civil 3D to create a differential point group based on the as-built points and the design surface, without going back and force and using Excel or Civil 3D Tools

Re: Point to surface comparison

ChrisRS — Wed, 09 Jul 2025 06:32:36 GMT

It looks like you are new to the forums. Welcome!

I am not sure what you want for your report. More detail or a sketch would help.

As I understand it, you have a design surface (DS) and as-built points.

I suggest the following approach.

Use the as-built points to build a new surface. (AB)
Create a TIN Volume surface using DS as Base Surface and AB as Comparison Surface. (DIF)
Create a Surface Spot Elevation Label Style, for placement on DS, that included reference components s for AB and DIF.
Text:: Design: <[Surface Elevation]>
Reference Test (Surface): As-Built: <[Surface Elevation]> After placement, pint to AB
Reference Test (Surface): Difference: <[Surface Elevation]> After placement, pint to DIF
This label can be placed directly on the points, or at random locations. If placed away from a point, it will refer to the interpolated AB surface.

Sample:

Design: 1125.50

As-Built: 1124.90

Difference: -0.60

Good Luck!

Re: Point to surface comparison

saeid_hajahmadi — Wed, 09 Jul 2025 06:49:18 GMT

Thanks, I was using my company account previously.

Thanks for your response, but the way you suggested is not what I'm looking for. Ideally, I want to see the differences and AB heights with different styles on top of each other, the fastest way that is possible. Imagine having thousands of points, Spot Elevation on the volume surface won't help me. I modified my points to design surface elevation and compare them to the AB points and import them into my drawing in different point groups, which does what I am after. I was wondering if there is a way to do all of these inside C3D and not using Excel for generating the differences.

Here is an example of what I am after.

Re: Point to surface comparison

SaeidHajahmadi — Wed, 09 Jul 2025 06:51:17 GMT

Re: Point to surface comparison

ChrisRS — Wed, 09 Jul 2025 07:13:47 GMT

I'm glad you found a solution. The positioning and color coding you show can be done with spot elevations.
I am interested in how you extract the design elevation at each point to Excell for the difference calculation.

I see that snapping to every pint would be tedious. There may be a lisp or dynamo script to automat that. Link: adding-multiple-labels-general-spot-elevation-by-selecting

It would be great if Point labels allowed reference text.

Re: Point to surface comparison

nkiakas — Wed, 09 Jul 2025 08:49:25 GMT

Hi @saeid_hajahmadi

Can you please clarify your attachment?

You have the points in black circle+x as points style.

Then i guess the black value is the as build elevation.

What are the blue and green values? (look like elevation differences, but what with what?)

Regards

Re: Point to surface comparison

andrewpuller3811 — Wed, 09 Jul 2025 22:15:23 GMT

Attached is a lisp that Timothy Corey (that I modified slightly) created that outputs a csv with the Point Number, Easting, Northing, Point Elevation, Surface Elevation and Distance To Surface.

You could modify the output in excel to remove the point number, Point Elevation and Surface Elevation and then reimport it.

You could also modify the lisp to output just the Easting, Northing and Distance To Surface.

If you are not familiar with lisp, you save the file somewhere, then drag it onto you civil 3d window, then run the command PSReport.

Re: Point to surface comparison

saeid_hajahmadi — Wed, 09 Jul 2025 23:51:40 GMT

Chris, I select one of the points and when the new tab for Cogo Point pops up then I go to Elevation from Surface icon, then change all the points by group and then I have the as-built points but in design height, then export them and do the calculation in excel as no I have 2 sets of points, one in as-built height and one in design height but in same coordinates.

Re: Point to surface comparison

saeid_hajahmadi — Wed, 09 Jul 2025 23:53:26 GMT

As you said, blacks are as-built values and blue and green are the differences from design which blue means within tolerance and green means above tolerance.

Re: Point to surface comparison

saeid_hajahmadi — Fri, 11 Jul 2025 00:51:47 GMT

Thanks for that, in civil 3D itself you can simply change point height to surface heights and export it to CSV and compare. What I wanted was an automated way of doing this without using a third party. I wrote this plugin attached which does this.

Saeid.

Re: Point to surface comparison

dayll_cohen — Sat, 22 Nov 2025 04:04:38 GMT

Thanks Saied, exactly what I needed!

Re: Point to surface comparison

saeid_hajahmadi — Sat, 22 Nov 2025 04:58:18 GMT

No problem mate, glad it helped

Re: Point to surface comparison

ty849 — Tue, 17 Feb 2026 18:23:57 GMT

sIR,

I HAVE TRY THIS NETLOAD ITS WORKING GOOD. BUT AS U SHOWN IN VIDEO PONITS NUMBER ARE SAME IN YOUR COGO POINTS LABELS BUT MY POINTS NUMBER IS COMING DIFFERENT FROM THE EXISTING COGO POINTS NUMBER COULD YOU PLEASE GUIDE ME WHERE IS THE PROBLEM.? HAVE U USE ANY CUSTOME POINT STYLE FOR THIS DATA.?

Re: Point to surface comparison

saeid_hajahmadi — Wed, 18 Feb 2026 00:08:25 GMT

Hi, if you install the plugin I wrote and I put it in my response it will generate points for the differences and you can simply change the style as you wish. I didn't wrote the lisp provided above and not sure how it works.

You can use any point style as you wish as it generates points with description. I can help you is you attache your file and let me know what exactly you need.

Re: Point to surface comparison

ty849 — Wed, 18 Feb 2026 04:46:36 GMT

Thank you @ Sir saeid_hajahmadi for replying me. I have attached two files. The thing is that points which are already in Asbuilt.CSV file, when elevations are created from surface using these points, then new points that are created should show same point numbers as I have in Asbuilt.CSV with the elevation difference that the application is already showing. I hope you solve my problem. Thank you!

Re: Point to surface comparison

saeid_hajahmadi — Wed, 18 Feb 2026 04:58:41 GMT

You can not have two points with the same number, all you can do is to put them in 2 different point groups and have one showing the number and one not. then you will see one number for your points on top of each other.

Re: Point to surface comparison

ty849 — Wed, 18 Feb 2026 05:22:15 GMT

Thank you Saeid_hajahmadi. Is it possible to add surface elevation label also along with surface elevation difference label? Thank you!

Re: Point to surface comparison

saeid_hajahmadi — Wed, 18 Feb 2026 07:47:26 GMT

It is possible. If you install the plugin I attached, you will have the point height, surface height and the difference. Then you can import them as you wish.

Re: Point to surface comparison

ty849 — Wed, 18 Feb 2026 07:54:57 GMT

@Sir saeid_hajahmadi. Thank you so much.

Re: Point to surface comparison

saeid_hajahmadi — Wed, 18 Feb 2026 07:56:56 GMT

If it was helpful, please like my comments. It would be much appreciated.