Forums >> Revit Building >> Technical Support >> topography not being generated at the correct level

EricHenyey

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Joined: Fri, Jun 22, 2012
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     I am having trouble getting Revit to generate my topography correctly.  The toposurface seems correct but the contour lines generated are offset 8" vertically from where they should be, and are labeled incorrectly.

     I have a level called "Sea Level" in my project.  This level is at elevation 0'-0".  I have a CAD file placed at "Sea Level" with zero offset.  The CAD file has contours which are located at elevations which are exact increments of a foot (e.g., 334'-0", etc.).

     However, when I generate the topography (Toposurface > Create from Import > Select Import Instance), the contours on the surface which is generated are not correct.  In elevation, the toposurface conforms to the CAD contours, but in plan and elevation the Revit contour lines are offset.  For example, the major contour line which Revit labels 340'-0" actually appers at elevation 339'-4".  If I move the toposurface 8" down, the contour lines are close in plan, but the toposurface is wong in section and the contour lines still occur at the wrong locations in section.

     I have to imagine that I am doing something wrong, because at one point in the project's development, the building got moved down by 8".  However, I don't know what I am doing wrong.  The project base point and survey point are both at elevation 0'-0".

     The problem is not the CAD file, because when I start with an empty Revit project, import the CAD file, and generate the topography, everything works correctly - the Revit contour lines exactly match those of the CAD drawing.

     I'm using Revit Architecture 2013.

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WWHub

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The problem is the CAD file - not Revit.  It doesn't matter where you place the CAD file.  The contours are dependent on the CAD file contour line properties.

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EricHenyey

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Joined: Fri, Jun 22, 2012
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Thanks for the response.  I don't think the problem lies with the CAD drawing, though, because when I import it into a different Revit project and make the toposurface, the contours work properly.

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WWHub

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Check your level properties then.  Your level 0-0 is project - not shared.  What you call 0-0 is something else in the real world.

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EricHenyey

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Joined: Fri, Jun 22, 2012
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I think that Revit 2013 changed "shared" and "project" to "survey point" and "project base point" - at least, those are the only two options for Elevation Base in the Type Properties.  I've tried both (re-importing the CAD drawing and re-generating the toposurface each time) but I experience the same problem.  (That's understandable, since the survey point and the project base point are the same plane.

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WWHub

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It doesn't appear that you understand the difference level settings we have available in Revit.  Watch this video that is from YOUR HELP:

http://wikihelp.autodesk.com/Revit/enu/community/videos/003_Site_Creation/Toposurface_with_Sea_Level_Elevations

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EricHenyey

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Joined: Fri, Jun 22, 2012
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That video doesn't help.  I understand how to set up the levels so that project elevations differ from sea level elevations.  That is not what is happening in my project.  I am using sea level elevations as the project elevations.  Revit is acting as if there were an 8" difference between the project base point and the survey point; however, in my project, there is no vertical difference between the two points.  They are in the same horizontal plane.

Does anybody else have a suggestion?

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EricHenyey

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Joined: Fri, Jun 22, 2012
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A bit more information:

My project base point is located at the Startup Location.  (When I right-click on it, the Move to Startup Location option is grayed out.)  When I click on it, it shows zero E/W, zero N/S, and zero elevation.

My survey point is located at the same point.  When I click on it, it shows zero E/W, zero N/S, and zero elevation.

Here http://forums.autodesk.com/t5/Autodesk-Revit-Architecture/Toposurface-contour-line-issues/td-p/3709130 is a link to someone who seems to be having a problem almost exactly the same as mine.

Any idea why my contour lines are showing up in the wrong place?  The topography looks accurate, but the contour lines appear to be incorrectly located and incorrectly labeled.

- Eric

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sconnie77

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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.

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auris901

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I have similar problem. All these two surface altitude is 160.000 but how you can see, the right one is one meter higher? why? And by the way, when I modificating toposurface, the surf point is 159200, but when I check it with sport elevation it show that is 160100. Why is that? 

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WWHub

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Put a tag on both surfaces....Also, check your rounding settings on your elevation tag.

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