Forums >> Revit Building >> Technical Support >> Toposurface glitch?

col9000

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Hi,

I'd appreciate any help I could get on a problem I'm having with toposurface points:

It's a little complicated to explain how I arrived at this situation, but basically the revit model was built, then later relocated vertically so that the ground floor would have a project coordinate elevation of 0.00m, and this would correspond to a shared coordinate elevation of 33.47m (the actual datum level on site). This all seems to have worked fine. However, when I now try to construct a toposurface around the building, topo points that should be just below ground floor level end up creating a topo surface about 100m below the building. If I place a spot elevation on that topo surface it give me an elevation consistent with that, of around -100m. 

So, anyone know why my topo points seems to be unrelated to everything else in my project? I can attach some images if that would be of any help,

Thanks

C

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col9000

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Actually, the plot thickens...

When relocating the project initially, the project base point was moved upwards (unclipped) to meet the ground floor level of the model (as I mentioned above, ground floor level is now 0.00m). This base point was originally about 100m below ground floor level, so those problematic topo points are relating somehow to the original project coordinates.

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Kronny

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Joined: Thu, Sep 9, 2010
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Hi,

Topo surfaces in Revit could do with improvement and are often the subject of criticism.

Thanks.

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WWHub

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col9000

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Hi,

I used the relocte process. I moved the project base point first (while unclipped), then when it was where I wanted it, I altered the shared site elevation field within the base point. However it's possible that the model was previously moved vertically, using the move tool to move the model.

I actually just tried to move the model down again using the move tool, with the intention of fixing the base point etc. afterwards, but the model might be too complex now, revit gives me a "serious error" message when I try to do it

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iamian33

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Did anyone out there figure out a resolution to this issue? 

This is very similar to an issue I am having with my TS.  My project was origninally created at ELEV = 0.  Then I used the Relocate Project command to set the model at the correct (datum) elevation and developed the TS based upon the surveyor's data file, at the correct elevation.  

Now I need to update my TS to reflect the current Civil and Landscape information, but when I edit the TS, the points are no longer the absolute numbers (relative to sea level) I used to create the TS, they are relative to the project base. 

I have submitted a support request from Autodesk but they seem to be stumped ... suggesting that this would be a nice feature ??^%$^??  (Thanks ... autodesk)

Short of pulling out the calculator for every new point I must add/correct, anyone have a suggestion on how to correct this?

Ian

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mongopac

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Wow....this is from 2010, and I just posted a similar problem in 2013 in the new Revit 2013?. 

How many versions ago did they know about this problem? 

Tsk, tsk.....

Come on, Autodesk.

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iamian33

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I had forgotten about this post. Honestly I gave up on it when auto desk couldn't resolve the issue and decided to close the door.   But since I've been exploring shared coordinates, I'm curious if the project base point might be manipulated to correct this... not certain if that would solve the issue but it might allow reasonable inputs. maybe try un clipping the project base point and lower it so that the spots make sense. Or try to set the spots relative to a correctly located survey point. Just a few thoughts...Good luck 

Ian

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Ian Shafer

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CarlyMallon

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Hello,

I had the same issue where I had created a datum level at 0 elevation and then created a topo. When I put in the topo points the numbers were correct relative to the datum level but then the topo surface itself was 1200mm above my building.

It turns out the topo points are relative to the project base point (which had been elevated to 1200 by accident), but everything else was relative to my datum level which said it was at elevation zero (which in this case was 1200mm below project base point).

This is how I fixed it:

1. In a Section view I clicked "Reveal Hidden Elements" and found the Project Base Point.

2. Next to Project Base Point is some info text. You can change the height of the PBP by editing the number next to Elevation. I changed mine back to 0. This moved the entire project down 1200mm (including my datum level, which then moved to elevation -1200)

3. I changed the elevation of the datum level to 0 again.

And now my topo points and my spot elevations are aligned. But I do have to relocated some buildings so that they are at the right elevation now......

Hope this helps in some way.

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iamian33

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Carly,

Nice write up.  I suspected that the solution lay with the Project Base Point.  Thank you for clarifying.

Ian

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Ian Shafer

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CarlyMallon

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I;ve just read about another way to align my Level 0 with the Project Base Point:  by clicking on the level itself and then going to Edit Type in the properties box and changing the Elevation Base: from Survey Point to Project Base Point.

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