We recently were given some 3D models by a subcontractor that needed to be incorporated into our drawings. There was one model in particular that was rather large in file size considering that it was only a small part of our overall design for the project. And to top it off, the 3D model from the subcontractor was to be placed about 11 times throughout the overall model. Even when the large file was brought into the drawing as an XREF, many of the AutoCAD designers experienced loading times of about 10 minutes.

The file size of the large model is almost 50 megabytes even after trying many methods to reduce its size. The method that we found that worked wonders was to use a FLATSHOT representation of the 3D model as a substitute for the 3D model.

Here’s how:

Below is a view of the piece of equipment that is 50 megabytes.

3D view of 50 megabyte file

Below is a top view of the large file. This view is all that a majority of the designers needed to see in their drawings

The FLATSHOT command can be used at the command line or the tool can be found on the ribbon under the “3D Modeling” workspace under the “Home” tab > “Section” panel (dropdown) > “FLATSHOT”

Note: that the view that is currently being shown on-screen will be used to produce the FLATSHOT version of the model. Think of this command as you orient your view of a 3D model and then take a picture with a camera. That picture is now the flattened 2d representation of the 3D model.
Keeping that in mind, if needed we could go to the side elevation views of the 3D model and produce FLATSHOT versions of those views so that they could be incorporated into someone’s drawing as well – thus reducing the time of opening the larger file.

For this instance, I used the following settings to produce the FLATSHOT.

I suggest playing with the various settings to meet the needs of your particular project.

Once the FLATSHOT file is created it is a good idea to open the file and try to clean it up further. Some commands that might help are: OVERKILL, PURGE, JOIN, AUDIT

Below is a file size comparison of the large 3D model, the FLATSHOT version and the cleaned up FLATSHOT

Now that we have a 2D version of the 3D model, the designers simply unload or detach the larger model from the XREF Manager in AutoCAD and load the FLATSHOT version.

Note: it is important to assign a person to take resposibility of keeping the 3D model and the FLATSHOT version in synch. If the 3D model was to be altered or moved in some way, the FLATSHOT would need to be updated so that everyone is using the most current data. In our instance at work, the large 3D model was not going to change through the project so it was an easy 1-time solution.