Old Problem- How Fix 3d Origin.

[lopezfigueroa]

I know this forum is for testing new features, but there are some issues I've been checking for a while now in the hopes that they'll be fixed, and this is one of the things I haven't been able to fix in many years. In some versions it doesn't happen, but in others it comes back.
This is an old problem that I have been having in some versions of Archicad.
It happens when I insert a DWG file that is in UTM coordinates and that has 3D information that is important for me to visualize.
What I do is import the DWG file as a GDL Object and I import it in the original coordinates, for that I use the topographic point at 0,0.

The file is inserted in its original UTM coordinates, very far from the origin. Also when I import these CAD files they often have elements very far from the origin, there are times when users leave blocks, texts, dimensions, etc. out of place.

What I do is drag the object to the 0,0 origin of Archicad, convert everything to morph. I check the 3D and I delete the elements that are out of place or very far away.

Up to this point everything works perfectly, I save the file and everything is fine when I open it again.

But when I forget or when during the process something is very far from 0.0 and I save the file. The Archicad origin is altered, you only realize it when you open it again. Then the Archicad origin coordinates are altered and it is no longer possible to fix them.
The consequences, if you have altered the origin and you want to export your file to Google Earth, the coordinate of the file is altered.

I can correct the coordinates for the plan view and the floor information is exported correctly with the topographic point, but the 3D information remains altered, and it is not possible to return it to 0.0. What solution would you apply?

I'm not going to feel bad if you don't find the solution right now, because I have a "solution". When this happens to me, I literally have to create a new file and copy my work there.

But it has already happened to several colleagues who use geographically located files and we haven't been able to find a solution properly. Take your time.
Thanks, And greetings to all the programmers behind this great software.

In case you want to check I shared PLN file and DWG in ZIp.

Workflow correct

Work Flow When I forget to correct
I shared PLN file and DWG in ZIp

[Franz Sdoutz]

I've almost forgotten about Gauß-Krüger 3d DWG import and Export. Up to Arch 26 such was a mess. Archicad could litteraly run out of space (even for 2D) and whitescreen (no crash, but kind of frozen). Thanks for reminding me. I need to test this again in Arch 28.

[Franz Sdoutz]

Geolocated Archicad projects

For DWG exchange, this is basically an ancient workflow problem, but combined with IFC, we’re in trouble.

Surveyors (DACH) will provide and request Autocad DWG files (2D or 3D).

Hence I start my projects from scratch with a  Gauß-Krüger referenced 2d DWG specifying the site and end my Project with a  Gauß-Krüger referenced 2d DWG defining the excavation pit.

The most convenient way in Archicad to manage this is by setting Project Location and Project North to the reverse engineered Gauß-Krüger origin point (there are other less convenient methods for setting up, they all work fine though)

On import of georeferenced 2D DWG files the following settings will yield the correct position if and only if true north is set to the default drawing orientation.

DWG files will automatically align to defined north on import.

So, if there’s already a model, you want to retrofit to surveyor coordinates, the surveyor DWG needs to be placed and rotated manually.

Now Project Location also needs to be set/moved manually.

On DWG Export (2D/3D) this will result in a correctly geo-referenced DWG file, even though the displayed coordinates in Archicad are ALL WRONG (due to manually interfering?)

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IFC coordinate origin:

Project origin and location origin are still realistically 225 km apart.

Since there’s no offset (East, West) defined, I expect the IFC Models to be located at the defined origins respectively.

Changing IFC export settings will ONLY change altitude correctly but create a weird OFFSET in the XY plane.

Top view of different IFC export options:

Correcting for Altitude elements of both export options are just a view hundred meters apart, NOT 225 km as I would have expected.

Base Quantities are OK, so there’s no dimension error.

IFC location data for export option: project origin only 

IFC location data for export option: location origin only

I could not figure this out.

This is serious, when requested to integrate with other IFC models (Engeneering and services do not care for my Archicad origin point)

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Also importing these IFCs back into Archicad, resulted in unzoomable WHITE SCREEN! (As if Archicad was running out of space due to an unintended dimension conversion m --> mm)

[Franz Sdoutz]

Ähmmm

Is this intentional?

[JohnB]

I think you are misunderstanding the mechanics of project geolocation.

First of all, the POSITION of the RECOGNITION POINT must be indicated in the project location dialog box.

Likewise, with the GEOREFERENCING PARAMETERS, the GEODETIC DATUM must be indicated, which is usually WGS84, as well as the map projection (UTM) and the map area (section in which it is located).

This map area can be located at https://es.wikipedia.org/wiki/Sistema_de_coordenadas_universal_transversal_de_Mercator  

or on google earth.

After doing that, you have to locate the user origin at the recognition point

Once this is done, the relative coordinates change

and when returning to the origin of the system, the relative coordinates are adjusted.

I believe that by doing it this way, the coordinate error is adjusted

[JohnB]

in Google Earth have to change how to show latitud and longitud yo UTM (Universal Transversal Mercator)

and Google Earth show the UTM and Zone Map Information

Firs the Zone Map ( 18 N) and the the UTM coordinates

[lopezfigueroa]

Thank you for your very detailed response.
I know the process, in fact what is done is to import the dwg in its original coordinates and from there it is dragged to the origin of Archicad and then the UTM data is configured. The question is that if you forget to do this and Archicad is lost, how do you reconfigure the Origin to its original state? That is the problem.

[Franz Sdoutz]

3D DWG Import and IFC export: Since this is vital for my work – more ranting.

Again, testing my preferred method: retroengeneering the Austrian Datum (origin point according to Gauss-Krüger system) = inverting algebraic signs for intended project reference point in order to define survey point (see post above)

There a two import options for 3D DWG import: as GDL Object or “plain”. Both aligned from survey point.

For BOTH methods, the negative height of the survey point is IGNORED. Thus, all 3D DWG points are way above ground level 0,00 Archicad project origin.

Archicad PLEASE FIX THIS!

@JohnB Georeferencing parameters for IFC will NOT change a thing with 2D/3D DWG export, nor alter the exported IFC-file point of origin...

Project location parameters will also not change anything for exported files.

https://en.wikipedia.org/wiki/Transverse_Mercator_projection#Terminology

????

[Franz Sdoutz]

Just talked to an IFC Expert with Archicad:

When exporting georeferenced project locations to IFC option 1 should do the trick.

Option 3 is not recomended at all.

[Franz Sdoutz]

According to Archicad the z-value of coordinates will always be positive (above the 0,0,0 Archicad origin) upon 3d DWG import - regardless. 

For the time being this can't be fixed. Maybe in a future version ...