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Does C3D 2014 do vertical transformations?

22 REPLIES 22
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Message 1 of 23
AllenJessup
596 Views, 22 Replies

Does C3D 2014 do vertical transformations?

I have Lidar LAS files in UTM18 and need them in State Plane. Horizontally they come in fine to a drawing with the correct system set. Vertically they are still in Meters. I know a couple of workarounds. But I'm just wondering if there have been any advances in 2014.

 

We're still on 2012 but I'm testing 2014 I don't want to go through the whole process again if it's not going to work.

 

Allen Jessup


Civil 3D 2012 SP 3 / IDSP 2014 HF1
Dell Precision T7400, Xeon CPU 3.16 GHz
Win 7 Pro, 64-bit,12 GB RAM, Nvidia Quadro FX 4600



Allen Jessup
Engineering Specialist / CAD Manager

22 REPLIES 22
Message 2 of 23
Neilw_05
in reply to: AllenJessup

AFAIK it doesn't.

 

One of the workarounds is to bring the data into Infrastructure Modeler and then export it to IMX. However I've found that you can't clip a surface that is imported from an IMX file. What is your workaround Allen?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 3 of 23
AllenJessup
in reply to: Neilw_05

One workaround would be to use Corpscon to convert the LAS file if they're in ASCII. These don't seem to be, but I'm trying to see what Corpscon does with it anyway.

 

The other is to complete the surface in UTM18 and meters. Then XML it out and XML it into a State Plane US foot drawing.

 

Just got an error from Corpscon. So that's not an option.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 4 of 23
Neilw_05
in reply to: AllenJessup

A more common challenge for me is transforming NED files. I have not found any software that performs vertical transformations on NED files. Since NED coverages are in 1 degree tiles they take forever to process and overwhelm C3D. If the workflow requires processing the data multiple times (i.e import/export/import) it is simply too prohibitive. Until we get support for vertical transformations I need to find a way to pre-process this type of data.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 5 of 23
AllenJessup
in reply to: AllenJessup

I found a method in 2012 that works. Should work in 2014 too, but who knows.

 

Export the Surface to a DEM file in the original system then create a Surface from the DEM file in the new drawing. Watch out because you'll see the input dialog will read the zone from the DEM file. But you sill have to enter it yourself in the fields below. Why? I don't know.

 

I tried using an XML file which theoretically should work, but didn't. Does anyone know the proper workflow for that?

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 6 of 23
Neilw_05
in reply to: AllenJessup

Are you sure the vertical units will be transformed when importing a DEM? I had problems with that in the past.

 

I wasn't able to make an XML file work either. I've spent many hours looking for a solution to this transformation problem.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 7 of 23
AllenJessup
in reply to: Neilw_05


@Neilw wrote:

Are you sure the vertical units will be transformed when importing a DEM?


I have polyline contours in the same area that were done from photogrametrics 13 years ago. In areas where no construction occurred. The contours created from the transformed DEM file compare well. At least well enough that I'm sure I'm in the correct datum.

The key was realizing that I had to input the DEM file coordinate system in the import dialog even though it showed that it was reading it correctly from the file already.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 8 of 23
AllenJessup
in reply to: AllenJessup

It's almost as if anything to do with elevation transformation is purposely hidden. In the Export Points dialog box under advanced options the first choice of 3 is "Do elevation adjustment if possible" in both 2012 & 2014 help only the 2nd and 3rd options are covered. The first isn't mentioned at all.

 

I just found it described in 2013 help. You have to have created a point file format with a datum boot value. So it isn't useful for this type of transformation. But why is it not in 2012 help, in 2013 and not in 2014? Weird.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 9 of 23
AllenJessup
in reply to: AllenJessup

OK. I finally settled on a method. Takes a long time but gave me the best results. I extracted the points from the metric Surface. I converted the resultant AutoCAD points to Cogo Points (took 45 minutes for just under 130,000 points - did this during lunch). I exported the points to a NEZ csv file format and use Corpscon to convert it to my desired system.

 

I then used the point file that resulted from that conversion to build a Surface in my State Plane - US Foot drawing. That produces the best Surface. It's a little ragged but much better than any of the others. I can improve it with breaklines from another source and eventually with Survey.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 10 of 23
Neilw_05
in reply to: AllenJessup

Does the 45 minutes cover the whole process or just converting the points? If the latter, how long would you estimate the whole process takes (create the surface, extract the points, convert the points, export to csv, process in corpscon, build final surface)?

 

When it comes to DEMs, 130,000 points is a small dataset. Can we assume the process would take 5 times longer if the dataset is 5 times larger?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 11 of 23
AllenJessup
in reply to: Neilw_05

The 45 minutes was just to convert the points. But exporting the point file, conversion and creating a Surface from the converted point file doesn't take to long. Maybe 10 minutes of less.

 

You might be able to get a point file quicker using Data Extraction. I was going to take lunch anyway so I thought I'd let it run and see if it would create the points. BTW. Make sure that point creation is set to Automatic for Elevation and None for description.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 12 of 23
tyronebk
in reply to: AllenJessup

It is possible to non-uniformly transform a Civil 3D surface. Assuming the end result you are looking for is just a surface (or DEM/XML file extracted from a surface) then you can:

- turn the surface into a block (be sure to turn on non-uniform scaling and exploding)

- scale the block Z by 3.28084 (or as needed)

- explode the block

- if you look at the surface definition, a transformation has taken place (although the values given for the transformation are not useful to identify what has actually happened) and the elevations are now scaled

- note that this is a copy of the surface; the original surface is in the block definition; purge the block to get rid of the original

 

I'm not sure this is exactly what you are looking for but it does create a usable surface. If you are attempting to scale surfaces with a vary large number of points your results may vary.

 

This same non-uniform scaling can also be done with a bit of programming to bypass having to use a block. Extremely large surfaces can be adjusted in a few seconds with this method.

Message 13 of 23
Neilw_05
in reply to: tyronebk

When it comes to DEM's, the size of the dataset makes any multistep process prohibitive. We really need a way to either pre-process the data before building the TIN or simultaneously transform it during processing.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 14 of 23
AllenJessup
in reply to: tyronebk


@tyronebk wrote:

- scale the block Z by 3.28084 (or as needed).


That might work going from meters to feet within the same system and could have worked after I brought the data in to our current system. But it won't work going from one system to another. I'd have to test it against one that was already transformed to see. Transformation from one system to another involves more than a scale factor.

I'm happier exporting the points from UTM and using Corpscon to do the transformation. The files the Army Corps of Engineers developed for Corpscon are the same ones that Autodesk uses for transformations in Map and Civil in the U.S anyway.

 

Thanks for the suggestion.

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 15 of 23
tyronebk
in reply to: AllenJessup

All I was trying to state is that if you have already transformed the XY then all you need to do is correct the Z. The non-uniform block scales the Z and leaves the XY at 1.

Message 16 of 23
AllenJessup
in reply to: tyronebk

Yes. That would work in that case. I didn't mean to sound dismissive. I'm just finicky about using the proper transformation. We're going to be melding this with Survey later so I don't want to have to adjust much.

 

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 17 of 23
Neilw_05
in reply to: tyronebk

When I first saw your post I assumed you were suggesting exploding the surface, making the graphics into a block, rescaling the Z factor, exploding again and recreating the surface from the graphics. That process would take far too long.

 

Looking again more closely I see now you are just making the surface into a block, rescaling the Z factor then exploding it. That sounds like a doable workaround. I'll run some tests when I get some time.

 

Great idea.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 18 of 23
DaveDrahn
in reply to: Neilw_05

Along the same line, maybe saving one step, could be to bring the surface in and set it to a display style that exaggerates the elevation by the 3.28084, then explode it (twice) and rebuild a new one off the lines/points/contours/whatever.
Save the block making steps, but I guess pretty much the same.
Message 19 of 23

Use Global Mapper to convert the file to the required datum, projection, and units.

 

Set coordinate System in GM

Load Source file

Export elevation grid format. USGS DEM

Set output units on options tab

 

Creates a 1meg point file in 45 seconds.

 

Jim

Matrix3DSurveys

 

Message 20 of 23
Neilw_05
in reply to: MATRIX3DSURVEYS

As far as I know, Global Mapper does not support NED. Can you confirm that it does?

 

I've spent quite a bit of time looking for a utility that can transform NED files. If anyone knows of one, please pass it on.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com

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