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Autodesk / revit-ifc

IFC for Revit and Navisworks (2019+)
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How to use the new Projected Coordinate System Reference-GUI #255

Open eibre opened 3 years ago

eibre commented 3 years ago

Can someone guide me on how to fill inn the correct information in the new GUI?

AngelVelezSosa commented 3 years ago

@WawanSolihin .

WawanSolihin commented 3 years ago

The default value for the Projected Coordinate System Reference will be taken from Revit SiteLocation. It is typically imported from AutoCAD or Civil3D. Alternatively, when such information is not available, you can enter the EPSG code. For example 25832 for ETRS89 / UTM zone 32N (from http://epsg.io), When the focus leaves the filed (by pressing Tab, or moving the cursor to another field), it will automatically search and fill in the other information based on the internal DB. The Eastings and Northings will be dependent on the Coordinate Base chosen. You may refer to https://github.com/Autodesk/revit-ifc/wiki/Mapping-geo-reference-in-IFC4 for some explanation how it works.

eibre commented 3 years ago

I tried with 5950 http://epsg.io/5950 but it didn't work. Are not all EPSG-codes supported? 25832 + tab did work.

eibre commented 3 years ago

Why is it only "Shared Coordinates" that rotates the ifc according to true north? (when opened in Solibri) It seems that the eastings an nothings are measured along different axis when Project Base Point is chosen versus Internal Origin, shouldn't that be reflected by the orientation of the model in the ifc file?

WawanSolihin commented 3 years ago

There is no rotation in any sort. The illustrations show that on the ground the project looks like item 1 in the picture. In Revit it is usually placed in certain rotation convenient that cause the True North no longer pointing to the actual North (the project point +Y is) (picture 2). The rest describes how this can be used to correctly map so that Revit IFC exporter can get the right values for Eastings and Northings. The XAxisAbscisa and XAxisOrdinate is the direction of the X-axis in relation to the True North

WawanSolihin commented 3 years ago

I tried with 5950 http://epsg.io/5950 but it didn't work. Are not all EPSG-codes supported? 25832 + tab did work.

It seems that not all codes you get from epsg.io is recognized. The data comes from AcDbGeoData::coordinateSystem. I think it takes the information from "C:\ProgramData\Autodesk\Geospatial Coordinate Systems 14.07\NameMapper.csv". If you look at the content it does not have 5950, but it has the larger one EPSG:4258

eibre commented 3 years ago

There is no rotation in any sort. Yes, if you choose "Current Shared Coordinates" the IFC file will be rotated according to true north when opened in Solibri.

Is it possible to add the CRS-info manually if the EPSG code isn't recognized?

WawanSolihin commented 3 years ago

Currently not because we want to make sure the information is correct and consistent. Maybe we will provide a way to override in the next update, but it will be user responsibility to input the correct information

ziyike commented 2 years ago

@WawanSolihin hey, it's been more than a year since this discussion, it seems like this issue still persists. While understanding the idea of making sure the information for IfcProjectedCRS being correct, not supported seems worse than being wrong, right?

It seems like a different approach is provided, by mannually entering parameters like ProjectGlobalPositioning.CRSName and more may allow us to export to a usable IFC file... yet not quite, the information regarding ProjectGlobalPositioning are not fully utilized, if at all.

So, any suggestions? Please?

AngelVelezSosa commented 2 years ago

I'll let Wawan address the full question, but I want to understand your comment: "not supported seems worse than being wrong, right?" I would think that it would be better to have nothing instead of something incorrect, right? Or I am misunderstanding your statement?

WawanSolihin commented 2 years ago

The option to enter manually Projected Coordinate System information is available from 2023 onward. The use of parameters ProjectGlobalPositioning.* has been deprecated and should not be used anymore. With this override, user must take responsibility to enter the correct information.

ziyike commented 2 years ago

@WawanSolihin Much thanks for the information! Guess we have to provide addins to support this in previous releases on our own, cuz many of our user groups are stuck at version 2020.

ziyike commented 2 years ago

@AngelVelezSosa Thanks for your response! But I came here for a solution, not a debate.

AngelVelezSosa commented 2 years ago

Hi, @ziyike , not trying to start a debate but trying to understand the requirement. I often hear that an incorrect answer is worse than no answer, so wanted to hear if that was true for you or not. Perhaps there are cased where something thar is approximately correct is better than no guidance.