Adjusting Topography to amended Project Base and Survey Point

[Anonymous]

Hi 

So I have inherited a project and have received a topographical survey but the original model maker hadn't created their topography using this information. Now i have adjusted the survey point and project base point to reflect that information the existing topography in the project is now offset off the ground level even though the points when editing the topography is displaying these numbers. Is there a way to fix this?

Many Thanks,

George

[RDAOU]

You mention that you have adjusted survey and base point...

1. Which version of Revit are you using?

2. If earlier than 2020, how did you move the project basepoint?

3 In which format did you receive the topographic survey? .csv file, Cad file...?

You can work your topo in a separate model then link and topo and building model. Set out and align as applicable and use publish/acquire coordinates.

[barthbradley]

The points in a Toposurface are relative to the Internal Original of the Project, not to the Survey Point or Project Base Point.  

[Anonymous]

Hi,

I'm using Revit 2019 for this project. I moved the project base point in elevation by selecting the project base point and typing in the elevation level. Received the topography data in CAD format and spot elevations are points in the .DWG file. 

[barthbradley]

Position the CAD relative to your Project. For instance, if you got a Spot Elevation in the CAD the reads +100'-0", move the CAD Topo in Revit Elevation to position that Spot Elevation at +100'-0".   

...Wait a mnute! You are creating a Revit Toposurface from a CAD Import? If so, I got a way better workflow for you.  

[Anonymous]

Yes I am doing that because I linked the CAD. Tried to create toposurface from import but It seems as though that revit isn't recognising the .dwg file with the points from the site survey.

Couple of things to consider in this scenario;

• A topography had already been made but it was made when the project base point was at 0,0,0
• I have now come on to the project and now amended the site information so the levels are showing the correct sea levels 
• In amended the project base point elevation point to 138.94m (which is what the consultants have agreed is the level we are working from) the topography seems to be offset now and all our levels are offset by 138.94m as well as toposurface. 

So effectively is there a way for me to move all of these down because I have tried to use move tool as I thought amending the site model would be a simple fix, but I can only move the topo in the horizontal plane and not in the vertical?

Regards,

G 

[JasonLLINDNER]

Revit recognizes CAD import. It maybe created the surface but is in visible in that view.

When your Cad contain xyz points  and geo coordinates of site it  is better to make the tpography in a new file and use acquire coordinates from the CAD. After that you kann link both model and site and you can also use aquire or publish to share with the building model without needing to move the base point manually. Before revit 2020 the base point and origin were super confusing with clip and not clip

[Anonymous]

Relocate the project and move it down to the correct level.

Note that levels can be set to show either the height relative to the Survey point or the project base point.

[barthbradley]

I understand what is going on. Was the CAD originally Linked in via Shared Coordinates with Revit Acquiring the Coordinates of the CAD?  If so, all you needed to do was change the Survey Point Elevation.  That's it.  No moving of the Project Base Point or re-Linking of the CAD was necessary if the CAD Link was Shared.   Can you return to that original state? If not, you need to change the elevation of the CAD Topo, so it is in correct relationship to the Building and then re-Acquire Coordinates.  

[Anonymous]

So I asked the guy who originally made the model. He didn't acquire any cooardinates from the CAD as the numerical info was included in the surveyors .dwg which was set to 0,0 it was all the z axis data which was correct but the xy was in relation to 0,0 in the xy planes I think it may have been an export from a sheet view. But we have the NE numbers. So my reasoning for adjusting the site model is to do with having to annotate with spot elevations down the line so in testing that out that's when I realised that something was amiss. 

So he described his process;

• He modeled the existing  terrain in the existing phase of construction
• He then proceeded by creating the toposurface by placing the point and manually typing in the z elevation

Where I come in;

• I check the project base point and survey point and amend the z elevation
• I would normally check these elements before modelling any part of the site problem is sheets have been already made so I would try my best to keep to this file.

[RDAOU · Accepted solution]

From what you have described, the geo location has not been set up in your CAD. It makes more sence if you model the site in a different model and set it up shared coordinates.

Anyhow, if you say the elevations are correct, and you have the Northing and Easting, all you need to do is

1. place a spot coordinate at one point and record its elevtion 

2. use "Set Coordinate at Point" input its N/E and the EL which you have just recorded

You do not need to mess with the base point...the above will relocate it with the internal origin automatically 

Luckily they simplified that in 2020

[barthbradley · Accepted solution]

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@Anonymous wrote:

• He then proceeded by creating the toposurface by placing the point and manually typing in the z elevation

Where I come in;

• I check the project base point and survey point and amend the z elevation

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This goes back to my original post.  The points inside Toposurface sketch mode are relative to the IO of the Project, not to the PBP or SP.   There no relationship there to "check" -- or "amend".   Now the Toposurface as a whole, can be positioned with respect to your PBP and SP.  Another thing, Spot Elevations report distance relative to their "Coordinate Base" -- not the Toposurface itself.  

[helloABXYB]

Neither of the solutions fix my issue. For example, like the question says, when editing the topographic points directly, the point 0'-0" will revert back to the my revits original project base elevation, which was 61'-6". I've since changed my project base point to 54'-0". This shows in all my elevation and whenever I put a slope annotation. However, when I go to move an individual topographic point in edit mode and I type in 0,0 it will go back to the project's original project elevation at 61'-6". So I end up with an topographic point with an elevation that is 63-6" rather than 56'-0". Does anyone know why my topography has somehow linked to my original base point and why it didn't change when I changed the rest of my project's base point? 

Edit: Added information - The 61'-6" was the base point that I assigned to my project before I brought the topography in and is not the linked CAD's original base point. In case anyone was wondering. The cad topography I have is on a 100 acre site ranging from 30' to 200' so it was definitely something I assigned based on my tiny site within the much larger context of the CAD file. 

[gallego.BIM]

Still no solutiuon to this?

[barthbradley]

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@gallego.BIM wrote:

Still no solutiuon to this?

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Solution to what?  

[gallego.BIM]

I have got a topography in my project file in which the heights of the points do not correspond neither to internal origin nor project base, nor  survey point. (The project was moved and rotated several times (i know;) and i can't reconstruct how this occurred.)

[barthbradley]

So, you want to know if there is a solution to reposition a Toposurface that was mistakenly moved in your Project?  If so: NO; there is no "solution" or this.  How could there be? 

...I don't know when it got moved, but if it happened recently, then maybe a backup will have the Toposurface in the correct position relative to the building. If so, you could use that one.  

[gallego.BIM]

Thank you for responding. I know a topo can be moved, thats not what i was looking for..



When I edit points in all topographiess in the project, the heights indicated all differ by the same value. Apparently they are NOT the z-distance from Internal Origin (which is placed on the same height as the Suvey Point. )

Strangely, spot elevation tags on that topo all report the correct height, wheter they refer to Project base (relative height) or Survey point (absolute Height).

[barthbradley]

I'm not following, but the Elevations shown for the Points (the ones INSIDE Edit Mode) are relative to the INTERNAL ORIGIN of Revit.  Period. Stop.  Sounds like you are saying that they are not.  If so, how did you come to that conclusion? I think your methodology is flawed.  

You are welcome to post your file here for our inspection.  That might make it easier.  

[mitchcantlon]

did you ever resolve this?

i have the exact same issue - its driving me nuts