Autodesk InfraWorks

[#1]

I had heard from someone that when using AIM 2013 that you shouldn't change the default coordinate system. I suppose it makes sense as to why you wouldn't need to change it but what issues can crop up if you do change it? Or did I hear wrong?

[#2]

Autodesk actually told us to use the default coordinate system at the Tech Academy this year.  But, I have been quite successful in assigning the coordinate system right from the start.  I alway do and I will be showing it on AU Virtual as setting a State Plane coordinate system from the start of a the project.

[#3]

Tood is right: if all your source datasets are already given in a single consistent and specific CS, you can use that CS as the model CS as well and avoid some internal reprojections of your data during data import.

What you also can do is: leave the model CS at it's default value (LL84; WGS84) and just set the "user CS" (UCS) to the CS you would like to display the coordinates in the status bar at the lower left. You can change the "user CS" (UCS) in the model properties (AIM 2013: left click on the program icon at the top left; select "Model settings..."; change the "UCS" entry).

[#4 · Accepted solution]

Changing the Model CS during "New" and using a projected coordinate system will not increase speed or accuracy, or make it possible to import more data, but it will limit the possible size of your model. The only reason to change the default settings is if you plan to work directly with the model's SQLite file outside Autodesk Infrastructure Modeler.

The User CS is used to display coordinates in the status bar and for any other CS display. You can set that to any coordinate system at any time without affecting how data is stored in the GIS database or displayed in the 3D model.

[#5]

So, if all of my data is in the same coordinate system, I can assign that coordinate system to the model when I create it. After it's created, I can change the User Coordinate System to display the coordinates however I need.

If I have a data in different coordinates it's best to use the default coordinate system at model creation and just change the User Coordinate System as needed.

Does that sound right?

[#6]

That is right. Actually, you not even need to change the CS even when all your data is stored in one different CS. Projecting to LL always does work lossless for AIM.
In many cases, you will also be successful re-projecting data in an individual CS in AIM. But this depends on the CS you selected and on the input data as many CS have just a specific area which is valid. So here, you will face unexpected behavior in some cases.

You also cannot change the model CS afterwards, so once you run into such an problem, rebuilding the model may become necessary. Therefore we suggest not to change LL if you have no intend to work on the SQLite file directly or of cause policies. That way you will stay flexible for whatever data you will add in future.

about the User CS, you are right.