SketchUp
Procedure
Exporting SketchUp material definitions
Many objects that are commonly used in CadnaA can easily be modeled using SketchUp Make, for example buildings, roads, barriers or area sources using simple primitives. The only objects that cannot be modeled are point objects (e.g. point sources, receivers).
Select File Type „SketchUp Materials (*.skm)“ on File/Export menu (on German system)
To ease modeling and import, first export the current object appearance settings as so-called „SketchUp Materials“ (menu File|Export, file extension *.skm). Make sure not to use any special characters in the filename since SketchUp can read ASCII filenames only. For each CadnaA object type being importable from SketchUp a separate material file is exported using their appearance as set on Options|Appearance dialog (see Object Appearance).
The entered filename is used as the initial part of the filename string of the exported files.
Import Material Files to SketchUp Make
Proceed as follows:
- Start SketchUp Make (here assuming Version 16.0).
- Delete the default model via the 3D-view.
- Open the tray „Materials“ in the right part of the main window.
- Select the material list „In Model“ from the list box in tray „Materials“.
SketchUp Make 2016, tray „Materials“ opened, material group „In Model“ selected
- Drag each exported material file (extension *.skm) from Windows Explorer via drag&drop.
In the end, all material types resulting the from the export of CadnaA object types are listed in the tray „Materials“ (see below).
Note
You may export all materials in the tray to a so-called „collection“ applying the export features of SketchUp Make.
SketchUp Make 2016, having imported material files from CadnaA, here with tooltip for „Parking Lot“ highlighted
Modeling in SketchUp Make
The following section provides recommendations when using SketchUp for modeling geometry data. Respecting these recommendations will improve the quality of the data imported to CadnaA.
Note
This is not a SketchUp Make tutorial, thus assuming that the user is familiar with this software. Furthermore, it requires that the material names resulting from the export operation in CadnaA are not modified.
- Keep the geometry simple: Use simple polygons without any holes for all area-like objects and box-type objects (like buildings). Model roads, railways and line sources using connected lines (see Additional Information).
- Provide materials for all objects: When importing SketchUp files, CadnaA evaluates the (front-) material of every planar face or polyline whether the material's name matches one of the expressions given in the import table (see Importing the SketchUp model to CadnaA). CadnaA will try to convert the polygon into the corresponding object. It is the user's responsibility to assign correct materials to the objects in SketchUp. For example, a vertical area with the „Parking Lot“ material will most likely not work or result in an invalid parking lot object in CadnaA.
- Modeling a building in SketchUp: While planar surfaces with a valid material are easy to do, buildings have a height and should, therefore, be modeled as boxes. Since *.skp files can only store planar surfaces this results in six faces being passed to CadnaA. To correctly import buildings into CadnaA only the top surface („roof surface“) should get the material type „House“ addressed while the other surfaces stay to be unassigned. In case a vertical area source shall be attached to a building‘s wall assign material type „Vertical Area Source“ to the facade.
- Modeling a line source: Model line sources like roads using connected edges via the „Line“ tool (hotkey L). To apply the corresponding „Road“ material afterwards right click on one of the edges, select „Select -> All Connected“ to mark all line segments at once and apply the material using the „Entity Info“ window as usual.
- What are „components“?: Component definitions are a collection of faces and edges that form a bigger object. Components can be reused multiple times in the model and only differ in their position, rotation angle and scaling. Since CadnaA does not use complex geometric objects (besides 3D-Symbols, but those are ignored in the calculation) all component instances' faces are treated independently of each other. The component name (names in case of sub-components, separated by two colons „::“) is added to the Memo-Window for further processing (e.g by using the „Modify object“ command/action). Component instances may have exactly one material, but this will be ignored because material of each individual face's is used by default.
Example containing a building, a line source, and a parking lot
- Geodetic reference: SketchUp files can have a geodetic reference stated as a pair of latitude/longitude using WGS84 coordinate system. All coordinates in the model are considered relative to this point which is located at the local coordinate system's origin.
Importing the SketchUp model to CadnaA
Select the file via File|Import dialog using the file format „SketchUp (*.skp).
If the selected file refers to a specific geodetic system the user is prompted to select a coordinate system. Since SketchUp makes internally use of the WGS84 system, the „UTM“ system is appropriate. By clicking the button „Cancel“ no coordinate transformation is performed.
On import, CadnaA converts all distances to meters automatically. Check the imported data, for example by using the 3D-Special view. All objects that could not be resolved are imported as auxiliary polygons by default. It is the user's responsibility to decide whether some of those should be converted to CadnaA objects. For example, the ground and side planes of a building could be deleted. An object's ID and the Memo-Window data may help to decide which to keep for further processing.
Import Options
The „Options“ button offers the following features:
- addressing object type to object layer (see Allocate Object Type to Layer)
- Import only in a section (see Import only Section)
- Simplify Geometry automatically (see Simplify Geometry in the manual „Introduction to CadnaA“)
- option „Unknown Attributes to Memo-Variables“ (active per default): When active, attribute names unknown to CadnaA are imported to a memo variable each, listed in the Memo-Window of each object.
Note
Layer and group designation of objects imported are saved in string variables in the object‘s Memo-Window.
- button „Transform“ (see Coordinate Transformation)
- button „Open/Save“: opens/saves import filter settings
Object Geometries
The following table lists all objects that can be imported to CadnaA. All points within a polygon have to be coplanar (i.e. laying in the same plane).
| CadnaA object | SketchUp geometry type |
|---|---|
| Area of designated use | Polygon |
| Area source | Polygon |
| Barrier | vertical Polygon |
| Bridge | Polygon |
| Built-up area | Box |
| Calculation area | Polygon |
| Contour line | Line |
| Foliage | Box |
| Ground absorption | Polygon |
| House/Building | Box |
| Line source | Line |
| Parking lot | Polygon |
| Railway | Line |
| 3D-Reflector | Polygon |
| Road | Line |
| Vertical area source | vertical Polygon |
Additional Information
The following hints and information may be useful to know:
- Boxes (i.e. buildings) should only have their top face's material set.
- Lines contain only two points and multiple lines must be connected using the „Modify objects“ -> „Connect lines“ feature in CadnaA.
- 3D-reflectors should be used sparsely and carefully (see 3D-Reflector).
- Acoustical data like sound power levels cannot be stored in SketchUp files.
- In case of polygons the front material is matched first and if it is not set the back material is used instead. Lines can only have a single material.
- Some optional SketchUp properties (e.g. „Scenes“, „Camera“ or „Rendering Option“, among others) cannot be imported.
- Vertical polygons (i.e. vertical area sources) must be square to fit CadnaA's internal data structure. Use the 3D-Special view to verify this.