2D or not 2D: that is the question

It’s not just about creating Revit models!! (Other softwares are available)

I was recently talking to a client who didn’t realise that all the survey data that CGD collects is 3 dimensional. Whether it is a Topographic or building survey all data collected is 3D information. When a client asks us to produce floor plans, elevations or sections we are producing 2D information from the 3D data. When asked to produce a topographic survey showing only 2D information with the levels annotated we are removing some of the intelligence of the information collected.

Many of our clients do not want full Revit models, which is fine by us, but do they understand the advantages of collecting 3D data? I would like to explain some of the benefits.

At CGD Ltd all our surveys are done in 3D. In essence we collect data from the survey site and make 3D computer models of the land or building. For topographic surveys the computer model is called a DTM or Digital Terrain Model. We have been doing this for many years and we survey the land in such a way that the model is an accurate representation of the actual land. Without going in to detail it means that if asked, a level for any point within the survey area can be obtained, even if that point was not specifically surveyed. We are able to interpolate the level. This is much more difficult to do using 2D information and very time consuming.

3D surface over 2D surface

The image above shows a survey undertaken by us with the 3D data overlaid on the 2D data.

In a similar way (but different) buildings are surveyed such that an accurate 3D model can be created in a computer.

Having these digital models we can interrogate them to produce the required information. For example using a DTM we can quickly produce accurate sections wherever these might be required. And, if you haven’t specified the position of the section prior to the survey, we can still confidently produce a section in the full knowledge that the data will allow us to do this accurately. This would be much more difficult using 2D information with levels. We can also produce ‘Cut & Fill’ volumes etc. using the 3D data.

In a similar way with buildings we collect more information than is required to produce purely 2D floor plans, elevations and sections. Our 3D information allows us to produce sections wherever you want to specify them. And if you feel that you would like an extra section we are able to produce it from the data we have already collected. No revisiting site! We are able to take horizontal sections at different levels in a building which is very useful in heritage buildings and is often asked for in churches.

Finally, when we have processed the data from a building survey, we can produce a ‘Webshare’. I believe this is an extremely useful tool. It is like having the building in your office. You can view 3D views around each room. You do not have to visit site. You can even take measurements from it. Take a look if you haven’t already discovered its benefits.

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