by Dennis Collin
I was recently asked how to import GIS imagery such as Google Earth or Esri data into Revit. There are a lot of workflows provided via cloud services and products such as Forma or the Civil 3D surface transfer utility via the Autodesk Construction Cloud, but what about a method without having to use a Cloud solution or where these products are not available, desired or required?
One non cloud solution is to use AutoCAD or LT and make use of the geo-mapping function. I have described this process in a previous blog here:
Locate a drawing using a suitable location, address or post code etc. Clip the image to a drawn rectangle and polyline and turn the online mapping data off to show the cropped area.
Fig 1. Live online imagery can be captured and then saved as an offline version.
This image is slightly different from a regular linked image and will need to be converted to a suitable offline format image such as a PNG, TIFF or JPEG. By adding a bespoke Raster Image plotter, more control over image quality can be achieved. It is possible to set image resolutions measured in thousands of pixels which is more desirable for larger sites yet maintain clarity of detail. Note the 4K and higher size presets in Fig.2
Fig 2. Plotting a drawing to a high-resolution image.
I have written another post on creating such an output device here.
Configuring AutoCAD to produce Hi-Res image outputs.
Plot out a suitable hi-resolution image (4000x2000px) and save the resultant PNG,TIF or JPG image to a suitable location.
Fig. 3 Linking DWGs and Images is a similar process in Revit.
In Revit, link in the DWG, establish shared coordinates from it or from another suitable file. If the drawing doesn’t have a location, use a common reference between the AutoCAD drawing and the coordination model/file. This task is usually performed in a suitable ‘site’ view with a view range that encompasses elements at all positions and levels and will produce a ‘Google Earth’ style output.
If a 2D only view is required, link in the image saved previously and scale its cropped boundary to the boundary line visible in the site view, rotating it if required.
Fig 4. Stretching the raster image to reference to the linked AutoCAD linework
If the imagery needs to be visible in a 3D view, then the image can either be set as a material or a decal. The decal option is quicker and can be face based and scaled to a reference ground plane, floor or toposolid as desired.
Fig 5. Defining and configuring a Decal from the image plotted from AutoCAD.
Decal types are also accessed via the insert tab. They have some limited material properties such as bump maps and illumination if required. Unfortunately, if using Revit LT, decals are not available, although the image can be linked as a 2D element. Alternatively create a material to be assigned to the ground plane.
Fig 6. Stretching a decal in a 3D view.
The precise geolocation of the model can be represented by Revit’s Internal Origin point. This can be specified by the project location command. This is a very similar process to the AutoCAD function mentioned earlier, albeit without it showing live online imagery.
Fig 7. Geo locating the Revit project, with the precise point represented by the internal origin point.
Views can be placed onto sheets or exported as required.
Locating and coordinating Revit projects are just some of the topics covered on our training courses. Visit the Arkance UK site to get an overview of the courses on offer and talk to one of the team for dates and availability or if you have more bespoke requirements. We are here to help!
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