Question related to Georef workflow

General
1

Hi,

I have been looking forward to using the georeferencing and the introduction of the 3D tiles is a wonderful addition!

Now I am wondering about the correct workflow in a multi-model setup. For example, a project I am working on we discovered some 6 months ago that we have to export from Revit with the project units set to “meter” in order to have it show correctly. It is a stupid Revit thing they should fix … However it is only one example of a model that can have wrong geolocation.
For this project we have created in the beginning a testfile to make sure we could deliver for the as built phase in the correct way. Then we changed back our working units in Revit to mm (could be cm or even imperial for someone else). And those IFC exports are what we are using on a day-to-day basis in Qonic.

Now even when I add the ‘Correct’ IFC model to this project in Qonic and activate the 3D tiles, the position is wrong.
But when I create a new/empty project, and load the same model, it displays correctly. This tells me there is nothing wrong with the model or with Qonic’s interpretation. But there is something going on between different models in the same project.

So, what is the correct setup at this moment? Based on previous use of iTwin and my current understanding of how Qonic interprets this, I’d say the following:

  1. At the beginning of the project, create an IFC file that has the correct georeferencing (created with Revit, that means exporting with ‘Meters’ as project units). This model can have some dummy geometry in order to verify the location in tools like https://ifcgref.bk.tudelft.nl/, likely ifcLite or Qonic.
  2. Upload into Qonic as the first model in a project, so that Qonic takes this model’s georeferencing and applies it to the project.
  3. From now on, any model uploaded to the project that shares the same IFC origin as the original model will be shown in the correct georeferencing location.

@Jacob_De_Sutter, is this correct?

In case this is correct, then there is the following issue: in my active project(s) there might be a wrong Georeferencing assigned to the project due to mistakes in the (first) uploaded model with georeferencing information. Is there already a method to reset this? Or to force the entire project to adapt to a certain (specifiable) georeference?

2

Hi @Johan_De_Cock,

The way it is currently set up is as follows:

Georeferencing is shared Project Data, meaning that modifying your georeferencing for one model will influence it on all your models in the project.

When you first create a project in Qonic, there is by default no georeferencing set, until either:

  • you upload a model that contains georeferencing (either through Revit or IFC), or
  • you create a model in Qonic and set a coordinate system and coordinates of a survey point within this system,

whichever came first. From that point on, geolocation of newly imported models will be ignored.

This is our first line in the sand, we will provide more tooling eventually, e.g. to detect a mismatch in georeferencing when importing a new model, and choose to override or automatically transform that model so the georeferencing matches with the existing location. The exact details of this are yet to be determined based on user feedback.

So, reading your proposed workflow this seems like a correct approach. For existing projects you can still:

  • move the survey point with respect to your model (by selecting it and using the Transform tool), and/or
  • change the coordinates of this survey point and/or the coordinate system by selecting the survey point and changing its attributes in the Inspect panel.

This gives you manual control over your projects location. Does this answer your question about your existing projects?

3

Thanks @Jacob_De_Sutter! It confirms my understanding and good to know the future tools are still being formed :slight_smile:

Then for the current project:

This manually moving and changing is not really a good idea I think (I fear it will become inaccurate very fast). Now in my specific case, I could upload the correct model in a new project, then see the values of the georef coordinates. Then go back to my original project and edit the coordinates over there. That should give me the correct values.

Unless there is (but I presume not at the moment) a method to remove the current georeferencing in the project Data.
I think that could be a good first tool to add, to reset the georeferencing completely. Afterwards the first new model upload will set the georeferencing again.