This tutorial will cover some basic techniques for importing GIS data into Rhino—using the Grasshopper plugin—in order to create a 3D site model with basic building masses. This method generates NURBS geometry in Rhino, allowing you to use features like Make2D to export vector graphics.
This tutorial uses the TT Toolbox plugin for Grasshopper to read Excel spreadsheets.
TT Toolbox can be downloaded here.
This exercise uses a building footprint shapefile and visualizes the height of the buildings by extruding with height data in the shape file’s attributes.
For this exercise, we will be using the Building Footprint dataset for NYC Open Data.
Open ArcMap. (You will find it in your start menu under Programs > ArcGIS > ArcMap)
Add the Data to the map. Once you’ve added your data, it will appear in the preview window.
Using the selection tools, highlight the area you are looking to visualize.
Export the selected data as a new shapefile. Right click on the data layer and Data > Export Data
Make sure that the pull-down menu at the top of the export dialog box is set to Selected records, pick a location to save the file, and set the file type to Shapefile.
Open Microsoft Excel.
Open the exported shapefile database (DBF file extension). Navigate to the folder where you exported your shapefile of selected building footprints, and open the file with the .dbf extension. If you do not see this file in the Excel Open menu, make sure the pull down menu for visible filetypes is set to All Files.
Notice that the 7th column (assuming the first column is column 0) contains the data for the roof height or HEIGHT_ROO.
Save As this file as an Excel Workbook (.xlsx extension).
Open Rhino 5. Make sure your units are set to Feet.
Open up Grasshopper.
Load Building Footprints with the Import SHP component. Create a File Path component, an Import SHP component, and a Curve component. Right click on the File Path component and use the Set One File Path command to link to the exported shapefile (.shp file extension, or AutoCAD Shape Source file).
Note: the .shp component effectively converts from your Coordinate System in ArcMap to the Euclidean coordinates in Rhino. You can add as many shapefiles into Rhino as you like and they will align properly as long as they were created in the same coordinate system and projection in ArcMap.
Convert Curves to Boundary Surfaces. Connect the Curve component to a Boundary Surface component. This ensures that footprints with nested curves (courtyards) are only counted as a single item.
Connect to Excel spreadsheet. Locate the attributes spreadsheet with a File Path component. Right-click the File Path component, choose Set One File Path, and choose the Excel workbook you saved earlier.
Import data from Excel Spreadsheet. Connect the File Path component to a Read Excel Sheet component (from TT Toolbox). Connect the File Path component to the [Fp] input, and create a Boolean Toggle component (under the first component tab, Params > Input) and connect it to the R input. Set the Boolean Toggle to True to get the Read Excel Sheet component to import the attributes file.
Copy the Excel data into a Data component. Create a Data component and connect the Columns (C) output of the Read Excel Sheet component to the Data component. Right-click on the Data component and select Internalize data. While this step is not necessary, it will embed the data into the Grasshopper file and speed up the calculation process.
Now it is time to extract height data. Create a Tree Branch Index component and connect the Data component to the Data Tree (T) input. Then, create a Number Slider of integers, and connect it to the Tree Branch Index component’s Branch Index (i) input. Create a Split List component, and connect the output of the Tree Branch Index component to the List (L) input. Create a Panel or Number Slider component with the value 1 and connect it to the Splitting Index (i) input. Finally, create two Panel components and connect them to the A and B outputs of the Split List component.
You should now see the field name in the panel connected to A and the values in the panel connected to (B). Changing the slider connected to the Branch Index will change between all of the fields (this corresponds to the column number from the Excel file), and 7 should be the field HEIGHT_ROO in this example, which is the building height from it's ground elevation to the roof.
Create a Unit Z Vector component and connect the B output of the Split List to the factor F input of the Unit Z Vector.
Create an Extrude component, and connect the surfaces of building footprints from the Boundary Surface component’s S output to the Extrude components Base B input. Then connect the Unit Z Vector’s output (V) to the Extrude component’s Direction (D) input.
Bake geometry into Rhino. Right click the Extrude component and select Bake
Your GIS data will now be baked into Rhino.