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==Getting Started==
== Creating & Analyzing a Semi-Random City Propagation Scene ==
For this tutorial lesson, you will use a wizard to build the geometry of an urban environment. Click on the <b>Random City Wizard</b> [[Image:RandomCityWizardIcon.png]] button of the Wizard Toolbar or select the menu item '''Tools → Propagation Wizards → Random City'''. A dialog pops up and asks for the total city extents and number of buildings. Accept Select <b>Custom</b> option for “Select Scene Type”. Reduce the “City Extents” to 250 and accept the default values value of 250m and 25 for the city size and the total number of buildings in the scene, respectively. Change the "Max Building Height" Base Size to 60 20 and press the {{key|OK}} button. The wizard creates 25 buildings with random locations and random dimensions in an area of 250m × 250m centered at the origin of coordinates. Since the location of the buildings is totally random, there is a chance that your transmitter may fall inside an "impenetrable" building and becomes useless. In that case, you may change the location of your transmitter or repeat this process until you get an acceptable scene.
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Note that since the locations and dimensions of all the buildings were created using random variables, you may get a different scene than the one shown in the above figure. Next, click on the <b>Basic Link Wizard</b> [[Image:Basic link icon.png]] button of the Wizard Toolbar or select the menu item '''Tools → Propagation Wizards → Basic Link'''. A dialog pops up and asks for the total grid extents, transmitter height, receiver height and receiver spacing. Keep Change the Grid Extents and receiver (Rx) spacing to 250m and 5m, respectively, and keep all the other default values: grid extents of 250m, transmitter height of 10m, receiver height of 1.5m and receiver spacing of 5m. The wizard creates a single transmitter and a very dense grid of 51×51 receivers centered at the origin of coordinates.
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== Exporting Your Urban Canyon Scene ==
A fully random city scene changes very quickly with few mouse clicks. This is helpful at the beginning when updating the random variables until you get a desirable scene. After that, the random feature may not be useful. [[EM.Cube]] allows you to export your physical structure to a number of popular CAD file formats such as STEP, IGES, STL, <i>etc</i>. The STEP and IGES options export all the solid, surface, curve and point objects. The STL format exports only solid and surface objects as sets of interconnected triangles and ignores all the curve or point objects. This is more suitable for propagation scenes if you don't want to exports all the base location pointspoint radiators. CubeCAD is the module where import and export operations should normally take place. For convenience, you can export your physical structure from any module including [[EM.Terrano]]. However, you can import external files only to CubeCAD.
In the case of stereolithography (STL) file export, [[EM.Cube]] offers two options: ASCII STL and Binary STL. The latter format results in a more compact file. You can generate a triangular surface mesh of objects in CubeCAD. This mesh is what is exported as the STL file. [[EM.Cube]] allows you to control the shape and size of the triangular patches that are used to model your objects. Switch to CubeCAD by clicking its button at the top of the navigation tree. Then, clicking the <b>Mesh Settings</b> [[Image:fdtd_meshsettings.png]] button of the Simulate Toolbar in CubeCAD or use the keyboard shortcut {{key|Ctrl+G}} to open the CAD Mesh Settings Dialog. Change the value of '''Mesh Cell Size''' to 100 units. This will generate very large triangular patches or cells. The parameter '''Mesh Cell Size''' is the counterpart of '''Cell Edge Length''' in [[EM.Terrano]]'s SBR Mesh Settings dialog, which you already encountered in Tutorial Lesson 3.
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Return to [[EM.Terrano]]. Once you finalize your random city scene, select the menu item '''File → Export...'''. The Windows Save Dialog opens up. From the '''File Type''' drop-down list, select STL. Use the Windows Explorer to browse you folders and decide where you want to place the your export file. Enter the a name , for example, "Random_City1" for your new file and click the {{key|Save}} button of the dialog. A new file called "Random_City1.STL" is created in the specified folder.
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== Creating & Analyzing a Fully Random City Propagation Scene ==
At this point, start a brand-new project all over again and repeat the the same steps of the previous section. First, create a random city scene using the random city wizard. However, this time, select <b>Urban Canyon</b> option for “Select Scene Type” and remove check mark from the box labeled '''Lock Location, Orientation and Size of Buildings'''. Using the basic link wizard, place a transmitter and a 51×51 receiver grid with the same parameters as in the previous section.
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<td> [[Image:TER_L5_Random.png|thumb|left|480px|The preliminary dialog of the random city wizard.]] </td>
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<td> [[Image:TER L5 Scene3.png|thumb|left|720px|The geometry of the fully random urban propagation scene.]] </td>
The transmitter is located at (0, 0, 10m) by default. Since the location of the buildings is totally random, there is a chance that your transmitter may fall inside an "impenetrable" building and becomes useless. In that case, open the variables dialog and click its {{key|Update}} button consecutively. Every time a new random city scene is generated. Repeat this process until you get an acceptable scene. Run an SBR analysis of the random city scene and visualize its received power coverage map.
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<td> [[Image:TER_L5_VarUpdate.png|thumb|left|480px|EM.Terrano's variables dialog.]] </td>
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{{Note|In the case of a fully random city scene, every time you update the variables, or regenerate the mesh, or run a simulation, the building parameters will be updated, and your physical scene will change completely.}}
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