Toposurface contour line issues

[russ.green]

I've got an issue with a Revit toposurface that I can't figure out.  I have a topo survey DWG with 3d contour lines.  This file was linked into Revit and a toposurface created from it.  The surface has been been and a graded regeion created. We've been working on the project for a while now and a recent site plan export to DWG flagged up an issue with contour lines.  The toposurface contours no longer match the DWG contours and everything is perfectly located.

I thought something must have moved but everything is still in alignment on plan and section.

To test this I've just created a new revit file and from scratch match the existing toposurface again from the same DWG.  The countour lines in the toposurface and DWG align perfectly.

So I know it works.  So I linked the new topo surface model into my problem model.  This view shows the result with the DWG contours turned OFF.  The surfaces align perflectly but the contour lines do not match up.

This is quite embrassing and I need to find a solution fast.

Any ideas?

Russ Green

[russ.green]

OK.  so I can at least be confident my surface is correct but for some reason my contours are actually being generated 250mm higher than expect.

[Anonymous]

Russ,

I am experiencing almost exactly the same problem that you describe.

In my case, when I import the CAD drawing into a new Revit project, I can generate a toposurface whose contours exactly match those of the CAD drawing.  However, when I import it into my existing Revit project, the contours are incorrect.  The toposurface itself conforms to the CAD contours, but the Revit contours are offset by 8" and appear to be incorrectly labeled.

At one point, I moved the building 8" vertically.  However, my project base point is located at the startup location, the survey point is located at the same point, and all elevations except for the contours appear to be correct.

Were you able to get a solution to your problem?

I'm using Revit Architecture 2013, by the way.

- Eric

[russ.green]

I have a support request in with AutoDesk at the moment...will report back when I know more

[Anonymous]

Sounds good, thanks.  I also have a call into our local support provider and will let you know if they are able to diagnose the problem.

- Eric

[Anonymous]

You have to define correct Z values for DWG polylines. Or set Passing Through Elevation value to an offset according

to your first polyline.

[mike]

As per the previous post, you need to adjust the "passing through" level, but you may then also need to relocate the project vertically to get the correct contour level tags showing up.

[russ.green]

I never really got an answer to this but I simply deleted both topo surface and DWG link and recreated both and the contours lined up perfecty.  Very odd.

[sconrad77]

The issue is the elevation value of the Project base point and the survey point (Blue Circle Represents Project Base Point and Blue Triangle Represents Survey Base Point, can be found in your visibility settings under Site). When you select the Project base point, make sure the elevation value is set to 0.  This should correct the Contours and the Labels.

[Anonymous]

I have a cad file with contours that I linked to the reit model. When I have created my topo from it, the contour lines are align with the ones in the dwg, they seem to be offet a few feet. Also I noticed that around the building it creates some weird contour lines that I can not get rid of.

Ive attacked a screen shot

[Anonymous · Accepted solution]

My building is model a zero level and now I want bring it up to my imported cad topo drawing but I don't know I have watch a video on survey point and project base point and made some adjustments but don't see any changes to my project

[Anonymous]

I want to rotate my building model on the topo surface but when I attempt to the topo is also rotating.

[Anonymous]

When a topo drawing is brought into Revit it generally comes at the calculated height above sea level?

[SteveFong]

Russ,

I know this is an old question for you, but I have been exploring these issues in Revit 2018; and since none of the responses to your question are answers, I am going to throw in my 2 cents! 

I am pretty sure that the contour lines of a topo are not based on the Survey point or the Project base point, but instead on the Internal Origin point.  This is a hidden point that can be found by unclipping the project base point, then right clicking it and selecting "Move to Startup Location."  This will reveal what the internal origin point is.  The Z coordinate changes if the project has been relocated in the Z direction.  This can cause contours to be drawn in strange locations!  

I can't find any way to reset this short of re-relocating the project.  

To get the contours to display correctly, you have to put the inverse (negative value) of the Internal Origin in the "Passing Through Elevation" in the Site Settings dialog box.  If you add any additional contours, you have to put the inverse value in the "start" portion of that contour.

[jendeena1.lightbourn]

So I am having a similar problem but it might be a different issue.  I have the topography and building at the proper elevation.  The building first floor level is set to 0' relative elevation, but I moved the project so that that elevation is really at 1087'9 3/8" above sea level.  I can verify this by setting my contour label to "Survey Point" and it displays the 1087' 9 3/8".  However, as you may notice, the contour line itself is being drawn AT 1087' 9 3/8", not 1087' and 1088' like it should be.  Obviously the topography is drawing its 1' contours in relation to the Project Base, not relative to sea level.  Any idea how to change this?  It know everything is at the right place in the model itself, I just want it to draw the contours on the toposurface relative to the actual topography.

[mike]

Take a look at the second post from the top, you just need to adjust the "passing through level" as an offset from your floor level.

This is on the massing and site tab, drop down arrow.  The offset should be the difference between your floor level and your 1' contour level.

[Adrian_2D]

The issue remains, in the 2020 version of Revit.

I didn't quite get the pass through offset stuff, could U share an image of that @mike?

And I usually insert coordinates to surveypoint & basepoint first then start on topo, does it need to be the other way around then?

[mike]

Hi Adrian,

If you are using a surveyors topo with co-ordinates, the contours should come in to revit in the correct place.  Here is where to find the topo "passing through" adjustment :

[Adrian_2D]

Excellent! Thanks I'll give that another go. 🙂