Is there a way to convert elevation datums?

[dsnyderGT3KW]

I do surveying work in Florida most county's want elevations to be listed in NAVD 88, with the exception of 3-4 that want the elevations shown in NGVD 29, there is typically a 1.5' ~ difference between 29 and 88. Is there an easy civil3d way to convert all my elevations on a file? 

Thank you for any info in advance. 

[_Hathaway]

If you haven't processed your drawing the easiest way is to edit the source data before it gets to the drawing. 

If it's already in your drawing and you have an existing surface you can select it, then raise/lower surface by the desired elevation.  IMO this is dangerous but may be the easiest.

I am sure there or more ways, as there often is in Civil3d, but those are the first that come to mind.

In those situations we always edit the source data as it's much easier downstream.

[AllenJessup]

There's a new Coordinate Transformation Tool for 2022. It will do Horizontal and/or Vertical transformation.

Also

https://knowledge.autodesk.com/support/civil-3d/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/Civi...

[Jeew-m]

I am not sure whether this helps.

But you can change the datum from the ribbon after selecting the required points.

[rl_jackson]

While I was unaware of the new tool @AllenJessup refers too, I'll certainly be testing it very soon, as I too, adjust data in FL between 88 and 29 along with the super special City of Miami datum (tool probably won't help there). However, if you're using the Survey Database you can do the vertical transform from there right in the SDB. I use either a Corpscon calculation or local NGS to make my 1.5~ adjustment (preferred).

Edit: If your not using the Survey Database, you can select all points and there is a Datum adjustment option.

[Pointdump]

Daniel,
The new Transformation Tool mentioned by @AllenJessup looks promising, but I only see transformation to Geoid models. I wonder if you could add NAVD29 and NAVD88 to the list.
Dave

[Pointdump]

Daniel,
Clicking the Help on the lower-right corner, I read:
"Select a target Datum.
The datum options are determined by an International Service for the Geoid (ISG) file of Earth Gravitational Models (EGM) installed to C:\ProgramData\Autodesk\C3D <year>\enu\Geoid Models.

There are many different additional models listed at >>>ISG-International Service<<< for the Geoid. The list includes a list of public, private, and on demand models encompassing over 100 countries (and with multiple versions of each)."
But I don't see anywhere to download NAVD29 or NAVD88.
Dave

[Pointdump]

Daniel,
I think I found the grid files for conversion between NGVD29 and NAVD88 >>>Here<<<. Not sure yet how to add them to the Transformation Tool.
Dave

[AllenJessup]

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@Pointdump wrote:

Daniel,
The new Transformation Tool mentioned by @AllenJessup looks promising, but I only see transformation to Geoid models. 

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 That's a shame. I haven't tested it out myself.

I'm a fan of Corpscon as @rl_jackson mentioned. But it becomes complicated if you're dealing with anything other than points. 

[dsnyderGT3KW]

i will have to check this out thank you for info 

[dsnyderGT3KW]

I have in the past only used corps con to covert a section corner, never even thought to look into vertical data shift, thanks for info