Selection via Image Maps
If you need to work with selections depending on an map layer or a map, simply define a boolean attribute for the selection that you require.
Using the terrain for selection
Your terrain layer contains an elevation attribute of a similar form like below:
attr elevation = map_01(brightness, 100, -100)You want to select all elements that have an elevation of 10 meters or higher. Simply add a new attribute that evaluates to true when elevation is bigger than 10.
attr high = elevation > 10
Boolean attributes in map layers are automatically added to the selection menu.
The resulting selection is shown in the image below:
By selecting a layer before selecting objects by map layer you can select only objects from the selected layer. If you have a layer selected that does not contain any objects this leads to nothing being selected.
Using a landuse map for selection
Landuse types are often used to define certain areas of a scene. The map below defines commercial (red), urban residential (blue) and residential areas.After adding the a new map layer with the landusemap, 3 new boolean attributes are defined in the Inspector view of the new layer. Depending on the color of the map, landuse types are evaluated.
Selection using the u,v coordinates of a map layer
For the following landuse attribute definition,
attr landuse = case u > 0.5: 50%: "industrial" else: "retail" else: "residential"
just add the following attributes to the same map layer:
attr isIndustrial = landuse == "industrial" attr isRetail = landuse == "retail" attr isResidential = landuse == "residential"
This will give you the following additional selection possibilities in the context menu:
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