Forums >> Revit Building >> Technical Support >> Topography points starting out with a negative offset

ericlovell

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Joined: Mon, May 10, 2010
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So this is a weird one that I just can't seem to figure out. A project at my firm is trying to do topography in Revit so we can have a correct site plan and whatever. I have set the project base point and survey base point to the correct elevations and spots per the CAD file we got from Survey. I am not creating topography from the CAD file because they just draw it flat. Anyway... Whenever I start placing my topo points, I go to Absolute Elevation and have it just start at 0'0". After drawing in anything to that level, even though I would like to draw them in at the Sea Level Elevation of 128', I place a spot elevation annotation on the flat surface and it says it's -0'-10 1/4". I have NO IDEA how it's even possible that it always starts out this way. I can't figure it out and it even does this in our office template. What is happening?? Please Help

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WWHub

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Joined: Tue, May 16, 2006
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If you have a CAD file with topo lines, it is far easier to use that than to create your own.   Just edit the cad and pick each polyline and set its 'z' to the correct elevation.  Then import.  If these polylines are one continuous pline, you will be setting multiple points very quickly.

Ceating a topo by imputing points creates one that is relative to that view.

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ericlovell

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Thank you. I know how to do that. That still doesn't answer my question as to how I fix a topo surface drawing in at an automatic negative offset. This is happening in our template, like I said, and we need to figure out what the issue may be since we don't get CAD topo with correct elevations all the time. 

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WWHub

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There is a hard coded first floor in Revit that has been a problem for some time.   I will try to explain.

The points you are looking at on the site plan are all RELATIVE!!! to the level they were created from.  

1. Edit the site
2. select a point and tag it with a survey base elevation tag.  (MUST BE SURVEY REFERENCE !!!!)  (You can set up multiple types.)
3. Let's say it tags 10'  and you know it should be 128' (SURVEY) ...
4. goto an elevation
5. from the modify tab choose tghe site
6. now move the site up 128' minus 10' !!!!

When you try to edit the site again, the points will still be strange numbers to you because they are still RELATIVE to that original reference but ALL elevation tags (SURVEY, PROJECT, RELATIVE) will be correct based on your survey and project locations but not the edit site!  This is why you are far better off to use a CAD file or points file to create your topo.

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ericlovell

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Ok. Wow. That is a huge problem that should be taken care of by Autodesk. I think that I understand what you are saying needs to be done, but I guess I will just inform people that the best way of doing it is to do the busy work in AutoCAD. Hopefully one day this program will work intuitively in every aspect. I guess that sort of answers my question. Thanks

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Possible to specify the starting offset object?

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