Town of High Level in 3D
 

This is our first example where we could try real textures for building walls - before, in our City of Gävle in 3D example we had to use random pictures taken by our staff or donwloaded from the Internet.

In this case, the town of High Level supplied us with the following materials:

• Orthophotos in MrSid format;

• Front Photos of the buildings;

• Buildings and lots in Geomedia format. The attributes included roof tops and eaves, and the names of the associated front photos.

The total number of houses in the provided example was not very big (32 buildings), so I decided to digitize roof ridge lines using the orthophoto using MicroStation V8. Again, in our Gävle example we did not use the real roof structures, instead we applied a simple centerline extraction algorithm, which sometimes worsk well, but in many cases, it creates lines that are very far from being correct. For the town of High Level, we have more realistic roofs.

I also placed street light cells in MicroStation, and found a light pole model in Google 3DWarehouse:

The whole workflow looks similar to the Gävle one, but instead of random wall assignment, we join wall photos with actual walls by photo_id attribute in AppearanceAdder.

The photos had to be modified in order to fit the walls - I manually clipped them to the wall extents:

These photos are not true textures - they are not orthorectified, not cleaned from vegetation or vehicles. There are also only front photos of the building - I used the same photo for all four sides.

I also replaced building shapes with bounding boxes, so I didn't have to take into account real building outline. This saves a lot of time, and makes the process easier, however, as result, we can see some grass of every roof.

I think this simplification and lower requirements are quite acceptable for quick modelling with big numbers of features. For a particular feature of interest this might be not the best solution.

In this project I also added some steet features such as fence and steet light.

I used one of the building photos to make fence texture. Parcel overlay helped me to decide where fences should be placed - whenever we have more than 1 parcel boundary occupying the same place, we have adjacent parcels that have to be separated by the fence.

Light poles are more interesting example. I used pole points and street centrlines with NeighborFinder to calculate an angle to the nearest centerline. Later, this angle was used for rotating the copies of the original SketchUp model, so that each light is placed perependicularly to the closest centerline.

Another interesting trick here is placing SketchUp model, which originally exists in its own coordinate universe. It is achieved by extracting the original XY coordinates, replacing source geometry with SketchUp model geometry and offsetting the model to the original XY coordinates. In this example, we have a simple case when the center of the model lays at 0,0. If a SketchUp model is not position at this point, we need to calculate offset by extracting model coordintates from the original ones.

The workspace does not look very scary once it is divided with bookmarks:

The output looks as follows: