Absolute coordinates issue when importing model


#1

I was trying to import a 3D model from Revit to SketchUp 2016 pro. The model had been setup the absolute coordinates system and export from Revit as DXF format. When import to SketchUp with Preserve drawing origin option checked, the model looked very strange,please see the snapshot of the model in SketchUp.

When I tried to import google map to this model, both the google map and the model gone!

Please help me to work out this situation. Thanks.


#2

Preserve model/drawing origin puts your imported model far from SketchUp’s system origin.
The location you grab has SketchUp’s origin in its center. To see both in one viewport may not be possible (great distance between the two) making both seem to disappear (too small to see).

The screenshot may just show faces Z-fighting for the same location on screen, not much of a problem to correct.

Import the model without preserving its origin.


#3

Thank you for your reply. Yes, you are right, when preserved the coordinates, the model will be far away from the origin point of SketchUp. When loading a google map, the centre of the map will be at the origin point. What I am concern is the google map has its coordinates too (otherwise the model will not go to the right place when export it to google earth), how the software works with this? Is it the centre of the map moves to the system origin, or the origin moves to the centre? If it is the origin moves to the centre, why it doesn’t move to the centre (or some certain points) of the imported model? If it is the centre moves to the origin, why the imported model doesn’t move to the origin? What I need is to keep the absolute coordinates information within the model, wherever it is in Revit or SketchUp. Hopefully you can understand my question, as I myself almost get confused. Thanks.


#4

You need to read up about geolocating a model. SketchUp works within its own “abstract” model coordinates (x,y,z) but allows you to specify how they relate to real world coordinates.


#5

Thanks for your reply. As my best knowledge, the only way to geo-locating a model in SketchUp is to add a terrain by grab a google map into the software and then move the model to align them together. This means the model itself coordinates has been got lost (because when imported, the preserve drawing origin option has been cleaned) and take the new xyz coordinates from the terrain. Yes, it somewhat keeps the coordinates information of the model. However, I really want to see my geo-located model can match the google map automatically, not by manual moving. Any plugin can do this? Or maybe I need some front-line knowledge to refresh my brain.


#6

Your knowledge is lacking. Geolocation defines the relationship between the model coordinates origin and real world coordinates. Until a model is geolocated, there is no relationship, so there is nothing that can be lost by moving your model in model space. Conversely, once a model is geolocated, the model-space origin maps to the geolocation. As to manually setting the geolocation, look at Model Info->Geo location.


#7

Note that it is also recommended for Revit to keep the model at or near the origin point (in the “project coordinate” system), although the limitations there are not as strict as in SketchUp. Revit also has a “survey point” system that can be used to geolocate and orient the model to the real world - quite analogically to the geolocation in SketchUp. The absolute coordinates information is stored there.

Anssi


#8

I checked Model Info -> Geo location, and found even I kept Preserve drawing origin option checked when importing the model, it still was recognized as Not Geo-located by SketchUp. In this meaning, I understand what you are talking about. What I concern is how to make SketchUp read the coordinates information from the imported model, meaning recognize a GIS model as Geo-located.


#9

Yes. I want to keep the same GIS when export the model to SketchUp without any manual moving.


#10

The DXF format is just a simple 3D CAD format and it doesn’t have a geolocation feature. I don’t know of a way to get geolocation from Revit (or Archicad) to SketchUp intact (or the other way round).

Anssi


#11

Actually we can read the coordinates if importing the DXF GIS model into AotoCAD, meaning the coordinates information still in there.


#12

Of course you can, if the model uses absolute coordinates instead of relative (survey point…)

AutoCad differs from BIM applications and SketchUp in that it really doesn’t care if you are drawing a mosquito’s intestines or the solar system to full scale.

Anssi


#13

I know Autodesk software (and other software) are working in different way from SketchUp, especially the GIS. I just like to see if there has a bridge between them and make them work together without any issues. Yesterday my colleague told me that 2016 Pro version maybe has the feature to keep the coordinates, but seems no, again. I can work with them by manually moving the model for now, but I really, really, really want to see SketchUp can do it for me automatically, as I have so many models need to do so.
Maybe this is not an issue, just a development.


#14

have you tried using ifc exports from Revit imported into SU?


#15

As an aside, is the coordinate system you are using to place your model in Revit the same as used by Google Maps? For instance, in our parts, the digital maps use a local or national coordinate system.

Anssi


#16

Yes, I’ve ever using IFC model. Same thing.


#17

IFC exports from Revit use the coordinates and orientation as specified in the Location/Site dialog (a single project can have several “shared sites”). So if the model is far from the origin, it will be far also in IFC.

Anssi


#18

Yes, the same. WGS 84 longitude, latitude and elevation.