Survey 3D points dwg import wont create topo

[timandjo]

The surveyors output is from Autocad LT and contains points as well as separate level annotations. The points are all showing XYZ 

The surveyors originating dwg has no contours just points, annotations and lines.

When I import either as linked or CAD import the points are visible in 3D. I have tried:

• standard toposurface > select import instance - checking only the points layer comes up with "The surface must have at least three distinct Points" error.
• explode the import - the points all disappear
• separating out all the dwg and import only the points (no text, lines or separate levels)
• exporting from the dwg by command dataextraction into a csv list - this results in a horrible pattern of points and mesh lines all in one vertical plane (tried switching the workplane = exactly the same). There are about 600 points in all
• the levels are text objects with xyz attributes - importing these similarly not recognised

Any ideas - never had this before. Attached the originating dwg

[barthbradley]

You can't create a toposurface from that dwg in the manner you are thinking (Create from Import Instance).   It's just point data.  See if the you can get a Point File from the Civil Engineer.  If not, enter those points manually.   

...actually, with all with information, I'll bet there is base 3D mapping. Ask the Civil Engineer for that. 

[SteveKStafford]

AutoCAD points have no equivalent element in Revit, it does not have a point element...which means Revit doesn't see/recognize them as a valid element. If you extract the point values for x/y/z from the AutoCAD file then you could create a surface from that. Or as the previous rely suggests, see if they can provide a version of the file that has contours (lines/polylines) instead.

[barthbradley]

@timandjo: You can do it manually fairly easily.  It's just going to take some time and patience, as there are 287 points. Maybe you don't need all of them.  I mean, if you only need a Toposurface for the building site, then just place those points that are within and around the building site.   

1. Import CAD

2. Turn off all layers except for "Height Point" (target points) and "Height" (elevations). 

3. Activate Toposurface

4. Snap Toposurface Points to the target points and enter the Elevation displayed for that target point.   

5. Finish Toposurface 

[SteveKStafford]

I downloaded your file. The "points" have lines in them. I find that Revit is quite happy to create a toposurface from the lines that are on assigned to the Points layer, using Create from Import > Select Import Instance. You end up with four points at the endpoints of each line in the crosshair of the points. The only trouble is they don't appear to be at their indicated elevation.

[barthbradley]

I re-examined the dwg myself.  I don't understand the purpose of generating a Toposurface from it. It's a 222 acre pancake. Virtually no relief.  It doesn't even register a slope.   

...out of curiousity @timandjo, where's your building footprint located on this?  

[timandjo]

Thanks for the replies - its not flat and it's a quite small site with about
4m rise over about 50m. An accurate topo is important.



I think no one has been able to make sense of the export points so there is
some issue with the surveyors total station output interpreted through Acad
LT.



I have ended up with the manual method which has worked OK and took around
an hour to add a couple of hundred points and then shift the top in section
to align vertically with the current site model.



Any recommendations on what sort of point objects in acad dwgs Revit is
happy to use for a topsurface?

[SteveKStafford]

If the values on the height layer are the elevations of the points then there is roughly 5' of elevation change over the site.

[SteveKStafford]

I was assuming feet, now I know it is meters. As I mentioned in my earlier reply the toposurface tool will recognize the lines in the points (crosshair in the dwg you posted), as I showed in my image. The issue with that is they aren't at an actual elevation, just at zero. If they were at elevation (properties) the resulting toposurface would be too.

Usually a survey have contour lines and they are at their corresponding elevation. That works pretty well.

Points and Regions in AutoCAD don't have an equivalent. There is no polyline in Revit either but it does see them however.

[barthbradley]

What can say? Wrong Units.  Shoot me.  

@timandjo: You actually defined 287 points manually? Good for you.  I wouldn't have had the patience. 

...to answer you question: Any recommendations on what sort of point objects in acad dwgs Revit is
happy to use for a topsurface? 

Just ask the Civil Engineer for the 3D Mapping next time. 

[barthbradley]

---

@SteveKStafford wrote:

The issue with that is they aren't at an actual elevation, just at zero.

---

Actually, all the annos and points on the "3D XYZ" layer all at true elevations, making me think that they are tagging polylines that weren't included.  That's the info the OP needs

[SteveKStafford]

They are "below" zero in the CAD file. I'm not convinced the correct unit of measure is meter...looks more like millimeter to me if it is metric. Meter is a really big site ...and building.

[Anonymous]

Just wanted a resolution to this - use EATTEXT or LISP command to generate CSV file and tidy up in MS Excel before "Specify points file" under the Toposurface Create from Import tab.

Below are the 2 resources useful for this Topo-survey XYZ point cloud issue -

https://www.youtube.com/watch?v=Z6AcmVIaLN4

https://revit.com.au/generating-3d-topography-a-2d-dwg-file/

Bottomline - a CSV file is used when the Surveyor has not provided the 3D contour lines. Which is most of the time.