Hello,
We have been analyzing our ifc files exported at the office with visualarq ifc exporter.
Here’s our results :
There are mainly three parameters that influences the coordinates system (of the ifc file) and position of exported geometry in the XYZ space using VA ifc exporter :
1 - Geometry position in rhino’s xyz space (in reference to rhino’s global world origin) : as you said - no matter matter the modelbasepoint or earth anchor point, the geometry exported will always land in it’s original X,Y,Z coordinates. For instance, if you export a column that is placed at 0,0,0, it will appear at these same coordinates in any viewer.
2 - Rhino Earth anchor point : the placement of the earth anchor point in X,Y,Z space influences the local coordinate system of the IFC file.
3 - Rhino model base point : the placement of the modelbasepoint influences the global coordinate system of the IFC file. What i don’t understand is that this does not change the geometric position of exported geometry in X,Y,Z space.
What is mot unpractical with this is the first point. In order to have our exported geometry fit with other IFC files in the correct place for further project coodination, the rhino model needs to be placed very far away from the origin, at the exact X,Y,Z location.
For obvious reasons, it is better to model and work with geometries that are as close as possible to the world origin.
Until now we have not been able to export IFC geometry that has been modeled close to the world origin and make it fit in the right place when merged with other IFC files.
So what we don’t understand is how to export geometry (modeled in rhino near the origin) that will land at the correct place (with the other IFC models placed at correct X,Y,Z location) when opened in an ifc viewer.
I think the best thing to do is to use rhino’s native “modelbaspoint” command. In order to give a reference point with X,Y,Z values that would serve as a reference for IFC geometry placement.
I hope visualarq’s IFC capablities will get better in the future, espacially regarding placement and geo referecing. I really think what you guys have done is already huge and i hope you will take all of this to the next level because the industry needs it !
Cheers,