AEC professionals commonly work in coordinate systems. A development site is measured by a land surveyor, who produces a map in the local country coordinate system. In the UK this is OSGB.
The architect produces a design within that coordinate system, i.e. the design is drawn using those same coordinates in Revit, Autocad Archicad etc. There could also be a point cloud in the same coordinate system.
For ease of use we may have truncated the coordinates, i.e. applied a false origin so a point / position maybe:
E 350479.977 N 495874.865 Z 56.927 this becomes E 479.977 N 874.865 Z 56.927 the false origin being E 350000 N 495000 Z 0.000 we don’t usually mess with the Z value.
I have a design Revit model in this coordinate system, a point cloud and an FBX model which are of the existing scene. It’s the inside of an industrial steel frame building. I have cut away from the point cloud and FBX model the area where the newly designed production line is to be sited.
I am trying to combine these objects in TWM however on import all 3 drop in entirely different locations. I could roughly smudge the models together, however this is rough as toast.
Think Autocad using XREF, all 3 of these drawings / model data would align perfectly in-situ.
This is absolutely crucial for AEC professionals.
Imported Revit model
I can see that the pivot point of each model is 0,0,0, when I click on floor slab element the coordinates are -649.460 , -745.760, 46.36. These bear no resemblance to the actual coordinates.
Imported FBX Model
Pivot point 0,0,0 if I drag the pivot point into the model area using pivot edit, its coordinates are -408.98, 892.57, 56.93. Apart from the negative value, these to bear some resemblance to the position of the site.
Imported Point Cloud
The point cloud is centred on 0,0,0 over the starting base, so also completely in the wrong position.
The Revit project base point is E 910.000, N 410.000 Z 60.000 we do need coordinates to 3 decimal places by the way. This is where all 3 inputs are positionally.
TWM needs to be asking me the question on import, something like
“Preserve input coordinates Y/N” if N will be centred on 0,0
“apply false origin Y/N” so as above I could truncate the coordinates if I had a drone model in country coordinates and a model in local.
I appreciate this software isn’t Civil 3D, but this is basic but stuff.
I have been trying to work around this by changing the coordinates of the pivot point, but I cannot fathom its relationship to the models.
