Level of details, LoD, is a new concept that comes widely to our industry. We see the name in the Swedish Geoprocess standard, it’s a general term regarding BIM data in the form of solids.

LoD is referred to in steps 0-4 alternatively, using 0, 100, 200, 300, 350 and 400 but in “our” world, we use 0-4. The degree of detail simply indicates how detailed we describe an object, starting from two dimensions to three dimensions.

Thus LoD 0 is a 2D, or “2.5D” (that is, where there is 2D data and a height, but not several height positions). LoD 1 generally describes a house as a cube in 2D data with two heights. LoD 2 has more details such as roof, LoD 3 is even more specific with maybe a bay window and finally LoD4 has information about the inside.

In Topocad we use LoD from version 18. You can specify the general level of detail in the Project Settings, directly in the drawing or directly on the object. The drawing settings are used as a filter to show only those objects that have the degree of detail you specify.
The degree of detail can also be used in the filter function.

Why LoD?

There is a way to show different level of details depending on the objects different needs. For some data products it is sufficient to use 2D data, or “2.5D”. For example, in a map or even in a landscape model with a large extent where volume information does not fit.

When we begin to create city models, we need to use more detailed information and information in 3D. At least LoD1 is needed to present a city.

If we are in a civil planning project, a 3D detailed development plan, or a new road, we need to show the information with even greater detail. Then LoD2 is needed, where we show the exact shape of the roof, or on a road we also show slopes, sidewalks, refuges, roundabouts.

In LoD3 and LoD4 we begin to get very close to reality, maybe the level needed to sell a project to buyers in a house building project or show a complete infrastructure with lighting posts, plants, trees, and more.

LoD – not just for design

With Topocad 18 we can easily survey the level of detail and for later versions of 18, we will expand the functionality to survey volumes according to different LoD levels. For example, surveying a house in LoD 1 or 2 by surveying three points on the wall corner and then one or two points to create a height = volume.

If we are to create basis for models, the reality also needs to consist of volumes and thus surveying according to some of the detailing levels. With Topocad we make it easy to survey volumes, maybe even easier than surveying a two-dimensional map!