CityEngine: created by Esri, CityEngine (see figure 15) is a tool with a more.All CGA rules have the format Predecessor -> SuccessorImport DXF street data CityEngine street networks CityEngine street networks are attributed graphs, consisting of graph nodes (crossings) and graph edges (street segments). They can be generated with the street grow feature, created in CityEngine, or imported via an external file, such as DXF. Prepare street data for CityEngineworld information from both OpenStreetMap and Google Street View to reconstruct.
Cityengine Street Creation How To Prepare YourThe second rule says that each “Envelope” shape created by the first rule should be split along the vertical y-axis into “Floor” shapes of height 2.5, so four floors altogether. We could extend this simple example by adding rules for splitting each floor into the front, back, and side facades, applying different textures to these, inserting windows and doors, and so on. Street furniture with attributes such as size, type and rotation (points) CityEngine can make use of this data and generate close to as-built geometries by applying simple rules. Note: to learn about how to prepare your data for import into CityEngine, please see the 3DCity: Data Preparation workflow on the CityEngine resource center 4.3.3 Road Network Generation Tool.The leaves of the tree are the shapes that will actually make up the final model, while all inner nodes are intermediate shapes that have been replaced by applying one of the rules. The shape tree for the simple example would start with the “Lot” that is replaced by an “Envelope” shape, which in turn is replaced by the four “Floor” shapes making up the leaves (see figure below). The “Successor” part consists of a number of shape operations that determine how the new shape is derived from the input shape and symbolic names for the output shape(s) of the rule (which can then be further refined by providing rules where these shape symbols appear on the left side of the arrow).Cityengine Street Creation Archive File AndIn the Import window Select archive file and browse to the location of the downloaded file and open it. Select Existing Projects into Workspace and click Next. To import our project RMB in the Navigator window and choose Import.
Rules can still be applied to these models. They are basically static textured 3D models, but CityEngine calls them Shapes instead. The reason is that these models are Multipatches imported into CityEngine. If all goes well, you should see a similar image as the one to the right.Even though you clicked not to re-generate the models, you still see 3D buildings in your viewport. Re-generating your whole scene can be demanding on your computer performance, especially with large projects.) (if you get a pop-up, asking whether you want to regenerate models, click on NO. Cityengine Street Creation Update The ModelThe term CGA stands for Computer Generated Architecture. Try experimenting with different values and also for the other flats.The CGA shape grammar of the CityEngine is a unique programming language specified to generate architectural 3D content. The building will change form every time you update the model. Press Ctrl+Shift+G or click on the Update Seed button (next to Generate button). Notice the Variation_Mode under the Building Height parameters is set to Random. ![]() As for the Selectors, you can choose one of the following: top, bottom, right, left, front, back, side (all sides, except top and bottom) or all (all sides). The end result is a mass volume. extrude(axis, height) : This function will take the selected surface and extrude it along the defined axis (x,y or z) with a given height. The Start Rule indicates where to start generating of a model. You will get a window saying that there is no Start Rule found in “BasicBuilding.cga”. Select our new surface, RMB » Assign Rule File. » BasicBuidling.cga » Open. Now we have a much bigger and cleaner space to write our rules. Go to Window » Layout » Rule Editing Compact. You can drag the edges and expand it, but instead we will use one of the Layout presets. However, this process becomes tedious when we have hundreds of shapes. We can correct this by manually selecting the edge we want as front and go to Shapes » Set First Edge. As you can see, our front is facing the wrong direction. This edge indicates where the Front is. This is the so-called First Edge. Window » Layout » Default. Reset the layout back to the default if you haven't already. CityEngine will find the edge that is facing a street and make it the First Edge.Select the heightmap and the texture files for import Select the surface, got to Shapes » Compute First/Street Edges. Navigate to the folder data » Rasters and drag the file “ Texel_Noord_IDW+50.tif” to our Viewport. We will use an aerial photograph to generate a DEM model (DEM = Digital Elevation Model). First, we must load in the terrain of our little town. I will call the scene “ Cocksdorp.cej” (Cocksdorp is a small town in North Holland). This means that the height data is increased by 50m so as to compensate for a bug in CityEngine, where elevations below zero will be counted as “ No Data” values while importing. Select the file “ Texel_Noord_Luchtfoto.tif” in data » Rasters as the texture file and click Finish.You may wonder what that “ +50” is at the end of our Heightmap file. This 3D terrain will get its texture from the specified Texture file. The Heightmap file will be the raster file where we will extract its information to generate our terrain in 3D. In the next window, we will choose a Heightmap file and a texture file. Just select RD New and click OK. Select all roads shapes again, go to Graph » Cleanup Graph. Now let’s clean our roads shapes a little bit to optimize the vertices count and in turn, efficiency for our whole model. We can do this in the Command Window under the Inspector window of our terrain. At the time of writing this, there is no rules for Dutch roads, because it is a rather complex task. ESRI has added a library of rules, textures, and other assets like plants since CityEngine 2014.0. Next, we will assign a rule to our roads. Create a folder Buildings in our Rules folder and create a new rule, I will name it “ LOD1.cga”.Applying conditional statements to fix certain buildings We will have a look at different LODs (Level of Development), but first we’ll start with the most simplest and basic one, a block volume. Now it’s time to populate our scene with some 3D buildings. Generate the models for our roads and change the NbrOfRightLanes to “ 0” and the Centerline to “ White”. Then navigate to ESRI.lib » rules » Streets » Street_Modern_Simple.cga » Open. We will make use of the area size of our BAG shapes attributes. We will give any building with a height lower than 2.5m a standard height of 3m and any building with a plot size of 25m2 or less will also get that standard height. We will modify our rule to correct these anomalies. These are most likely storage sheds, unless it’s the tower of a church or something similar. You may also notice some tall but small buildings. Select the BuildingHeight map layer and enter the following offset values in the Inspector:Now, select all BAG Shapes and generate! You will notice some buildings with height values are not generated, select them and generate again. Navigate to data » Features » Trees and drag “ TreePoints.shp” into our scene. This is purely for visualizing. I colored the blocks red that are affected by our case statement. Remember to link attr Area to the Shapes Attribute: OPPERVLAK our of BAG Shape layer. The mask of dimitriosThis enables you to follow along more easily. First we’ll add realistic textures to the roof and the facades, then we’ll include windows, number of floors and doors.For the purpose of this course, we’ve added a python script which will select the Terraced Houses by its Attributes ID. Set the type to Analytical.Now we have our buildings in simple LOD1 form and our trees in LOD2.We’re going to select a few terraced houses and bring the LOD to the next tier, LOD3. Press F9 to run the script or go to Python » Run Script. Navigate to the scripts folder and open the python script “ SelectByAttribute_TerracedHouses.py“ by double clicking on it. The use of python scripts within CityEngine will be discussed more thoroughly in other courses. Scripting offers a broad range of possibilities. Handheld games for multiplication(hint: remember about the first edge?) Make sure that the textures for the windows and doors appear realistic. Complete the rule by fixing the middle floors and the top floor. Try to understand what the rule does. This rule is incomplete! Assign it to the objects and generate. Browse to the rules » Buildings folder and open LOD3.cga. ![]()
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