Topo from CSV coordinate location

[nathaniel.mcmahon]

I've linked a dwg file and using it's coordinates as the shared coordinates in my model. Note importing a CSV of surveyed Topo points in cuz format but the resulting Topo is created reading those values not in the shared coordinate space and I'm not even sure in the model coordinate space but somewhere else. I can manually move it but I'd like to know why this is happening.

[barthbradley]

What do you mean by: "the resulting Topo is created reading those values not in the shared coordinate space"?  Can you explain further?  It sounds like you have created a Toposurface from a point file, and inserted your CAD via Shared Coordinates which would place the CAD Origin at the Survey Point Origin.  Did it not?   

[constantin.stroescu · Accepted solution]

have a look at this previous post:

https://forums.autodesk.com/t5/revit-architecture-forum/toposurface-from-csv-file-do-not-align-with-...

[nathaniel.mcmahon]

Yep that's right. So topo points are loaded into project coordinates but they're based from sea level and a global coordinate system. I don't see how you can place these points in the shared coordinate system instead. 

[barthbradley]

I'm still not following. Toposurface zero origin is the Internal Origin of the Project (a.k.a. the Project Base Point's Startup Location).  

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@nathaniel.mcmahon wrote:

 I don't see how you can place these points in the shared coordinate system instead. 

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This is confusing.  You are mixing concepts.  Toposuraface Internal Points and Shared Coordinates are not related.   

[nathaniel.mcmahon]

Great thanks, Thanks exactly where I'm at. and I'm having to manually move the topo points. It's strange though because the points aren't precisely  lined up with the linked dwg they were extracted from. I was thinking this was due to them being placed so far away from origin in the model that they lost precision?   Not an issue you've had?

[nathaniel.mcmahon]

No worries. Constantin understands

[barthbradley]

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@nathaniel.mcmahon wrote:

Great thanks, Thanks exactly where I'm at. and I'm having to manually move the topo points. It's strange though because the points aren't precisely  lined up with the linked dwg they were extracted from. I was thinking this was due to them being placed so far away from origin in the model that they lost precision?   Not an issue you've had?

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You don't move the Toposurface Points. You move the whole Toposurface.   BTW: there is no correlation/connection between the Survey Point ORIGIN and the Internal ORIGIN of the Project -- unless you purposely place the Survey Point at the Project Base Point Startup Location.  

[barthbradley]

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@nathaniel.mcmahon wrote:

No worries. Constantin understands

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Okay.  Maybe @constantin.stroescu  can explain to me what you are talking about.

How about it, @constantin.stroescu? Care to share? 

[constantin.stroescu]

ok  barthbradley,

but, don't you think that this item was discussed before in the previous post which I mentioned above?

• In my opinion , due to the fact that Revit is limited in importing geometry to 20 miles I am forced to import Center to Center. Then I can correct this by acquiring the Coordinates from the CAD file. Agreed?
• When importing a .csv file and forced to place the result ( for the same reason of 20 miles limit) Center to Center the correct position of the Points is altered from start. That's why I have to move the imported entity manually to the right position. Anyway I don't know to be a method to acquire coordinates from a .csv file ( a text file not a CAD file) to fix the true position....

That is my way of thinking it , but I'm opened to other opinions.

Constantin

[barthbradley · Accepted solution]

Thanks for the reply, @constantin.stroescu.  Fundamentally, we see eye-to-eye.

What I was speaking to, was the OP’s misconception that the CSV Toposurface is relative to the Shared Coordinate System. It is not.  As I explained above that the CSV Toposurface originates from the Hidden Internal Origin.  

If you Link Origin-to-Origin, after you’ve created the CSV Toposurface, the Link's "Zero" Origin is also placed at the Hidden Internal Origin.  At that point, if the Link and the CSV Toposurface don’t align properly – and they are supposed to - then they obviously don't share the same Origin.  This is not at all unusual in my experience, and reconciling it is difficult.  But the bottom line is that one or the other needs to be moved to align them.  But, getting them to align precisely is near impossible. 

Once they are aligned with each other, move them both together to the correct position, orientation and elevation RELATIVE TO THE PROJECT THEY ARE IN, and then Acquire/Publish coordinates from/to the Link. 

[constantin.stroescu]

I agree with you! 

[nathaniel.mcmahon]

I've gone back the the DWG file and populated the survey points with z position (surveyors left it blank with a text note elevation tag) pulling the data out was getting the text tag node not the point so that was the cause of my errors. 

Imported directly from the dwg now and all is fine. Much better informed about coordinates now thanks. great resource available at revitpure.com

One new issue I'm having though as I'm working with a distant survey point. Rotating in 3D is operating on a massive turning circle making navigation near impossible, zoom extents is fine, survey point visibility off. Any ideas

[Mirko.Jurcevic]

I have an idea, if I may add to the discussion:

- in a floor plan, create line alinged (manually) to something on the topography, for example aproximately along the edge of the topography

- group together line and topograpy

- draw another line as a target (reference) on which to align the first line (topo edge)

- align line from the group onto the other (final) line

- ungroup

[nathaniel.mcmahon]

Another thing I'm noticing. The dwg that i acquired the shared coordinates from shifts when I move around or zoom. It's points shift in relation to each other significantly. 

Is this because it's internal origin is somewhere far away near the survey point perhaps?

[nathaniel.mcmahon]

Here's some images to illustrate. Madly erratic. The dwg was placed origin to origin the coords aquired from it.

[Mirko.Jurcevic]

Those things (flipping/jumping cad) happen when you have oversized dwg reference (which extends too far).

Try zoom extends in dwg and try making model area as small as possible.

Also, try using "crop view" in Revit, it may help.

[nathaniel.mcmahon]

the dwg isn't oversized really. Zoom extents fits the drawing nicely on the screen. 

in Revit crop view isn't helping either.

I'm thinking i possible inserted the dwg with the wrong placement method. I may have entered it via manual origin or center to center.

[barthbradley]

Move all the elements in the Project to within a 10 Mile Radius of the Project's Internal Origin. The Internal Origin is HIDDEN and FIXED (e.g. does not move), and it can be located by selecting your Project Base Point and unclipping it, and then right-clicking on it and pressing "Move to Startup Location".  The PBP will now be sitting at the Project's IO.  Note: If "Move to Startup Location" is grayed out, then the PBP in already at the Internal Origin.  

...this should correct the wonky linework you are showing in your screenshot above. 

FYI: 

https://knowledge.autodesk.com/support/revit-products/troubleshooting/caas/CloudHelp/cloudhelp/2019/...

[nathaniel.mcmahon]

How do I move the shared coordinate system with the elements?

Do I move everything reset the shared coord system then re acquire?