SST_1802 – Creating A Site Model

A site model is a 2D and 3D representation of a mathematical model that is based on 3D data. In simple terms, a site model is a 3D digital version of your site. You can use it for visualization, solar studies, cut and fill calculations, and much more.

Table of Contents

Beginner Topics

What Is A Site Model And What Can You Use it For

A Site Model is a way of looking at 3D data (spot levels or contours) in a way that allows you to see complex information as a simple 3D model. You can only make a Site Model if you have Vectorworks Architect, Landmark or Designer.
When you create a Site Model, Vectorworks will make an object that can show one type of information in a 2D view (2D contours) and a different type of information if you are in a 3D view (3D contours or extruded contours, etc.). Using this hybrid object is a good way of combining the 2D contours and the 3D Site Model into one object. If you are used to earlier versions of Vectorworks, then this will be a very different way of working.
Contours. If you put in a series of 3D spot levels, you can use your Site Model to show the contours, setting the height between the major and minor contours.
Visualization. You can create a 3D model of the site to help you see the building sitting on the site. Then you can use this to place your building, tree and landscaping. Or, you could use the model to show the client how the site looks from different angles.
Height In Relation To Boundary. You can use the model to analyze the height to boundary (recession) planes to see how close to the boundary you can build by cutting a section through the site, or you can place the building model on the 3D mesh and create your height-to-boundary planes to see if the building passes through these plans. If it does, you can see by how much.
Cut and fill calculations show the difference between an existing Site Model and a proposed Site Model. Solar studies can show the difference in the sun between summer and winter.

How Is A Site Model Made?

Vectorworks uses the 3D information to create a 3D representation of the data. The way it does this is to look at adjacent 3D data and create a 3D polygon between the nearest three points.
Then it looks at the next adjacent points and makes a 3D polygon between the loci.
Vectorworks carries out this process for all the loci.
The 3D polygons are combined into a site model. The extent of the polygons forms the extent of the site model.
When the site model is created, Vectorworks will create the 2D representation of the site model, the 3D model, and a mathematical model that includes all the data and allows you to create modifiers, cut and fill calculations, and the surface heights of the Site Model.
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How To Create Site Model Data

You need 3D data. You can use 3D polygons, 3D loci, stake objects. You can use 2D polygons or polylines and then run them through a command to convert them into 3D shapes.
The 3D data has to be selected, then use the Create Site Model command. This will use the selected 3D data to create the site model.

Import A PDF

One of the easy ways to create a site model is to import a PDF plan and place stake objects or 3D polygons on the PDF.

  • A PDF can be easily imported by using the Import > Import PDF… command or by dragging and dropping the PDF onto the Vectorworks drawing. Either method will give you the same results.


  • Once you have imported the PDF, it needs to be calibrated. If you do not calibrate the PDF, you cannot guarantee that the Site Model will be the correct size. It is so important that you calibrate the PDF—it cannot be overstated. Everyone that uses the file after you will assume that it has been calibrated. The PDF is calibrated using the Scale Objects… command from the Modify menu.
  • Select the PDF. Go to the Object Info Palette. Turn on the option to Snap to Geometry.


  • Go to the Menu bar. Choose Modify > Scale Objects…
  • Click on the button to measure something on the PDF that you already know the size of. I usually use a boundary, if it has a dimension. Whatever you choose, you have to know the true size of it.
  • Enter the known dimension.
  • Before you click on the OK button, ensure that the Entire Drawing option is NOT ticked. This option can resize everything in your drawing, and I mean everything—every line, object, symbol … everything in the entire drawing.
  • Click on the OK button to finish.


Import A 2D DWG/DXF

You often get plan information from a surveyor. This might arrive as a PDF (as above) or as a DFX/DWG file. A DWG/DXF file also needs to be calibrated. The way that we calibrate an imported DXF/DWG file is slightly different from the way that we calibrate a PDF, and it needs to be carried out in a new blank file. As a general rule, you should always import a DXF/DWG into a new blank document.

  • You can also drag-and-drop DXF/DWG files into Vectorworks to import them.


  • If you do not want to drag-and-drop your files, go to the Menu bar.
  • Choose File > Import > Import Single DXF/DWG File… It is important to use the Import Single DXF/DWG… command as it provides easy access to some settings that many users miss out on.
  • Locate the file to be imported.
  • Set the 2D/3D Conversion to All 2D.
  • Set the correct units and scale.
  • Convert any dimensions to groups, this will allow you to see the true dimension that the surveyor or architect added to the plan.
  • Click on the OK button.


  • Remember to check that the file has been imported correctly by dimensioning a  known object. It is very important that you check the file before you do anything else.
  • Go to the Menu bar. Choose Modify > Scale Objects…
  • Click on the Symmetric By Distance option.
  • Then click on the measurement button.
  • Use this to measure something that you know the length of, such as the boundary.
  • When you finish measuring (place the second click), the dialog box will reappear.
  • Type in the correct boundary length in the New Distance field.
  • Click on the OK button.


  • You should see another dialog warning you about scaling the entire drawing.
  • Click on the Yes button.
  • The entire file is scaled.
  • In this case, you have the 2D data that you need to create the Site Model.
  • Depending on the information you get, when you come to work on the contours, you might find that the contours are grouped together. In my case, everything has been imported as a symbol. To access the information inside the symbol, it has to be broken up.
  • The command to do this is Modify > Convert > Convert to Group…
  • Once you have converted the symbol into a group, it can be ungrouped, exposing all the native information that we require.


  • Surveyors’ drawings often use polylines for contours, but Vectorworks uses polygons for Site Modeling. The result is that you might end up with a contour line with 1000s of vertices. This makes site modelling slow, if the file is large.
  • There is a way to simplify the polygons.
  • Select all the polygons.
  • Go to the Menu bar.
  • Choose Modify > Drafting Aids > Simplify Polys…
  • This command will analyze the 3D polygons and remove vertices that are close to each other. The result should be a polygon that looks just like the original, but has only a fraction of the initial vertices.
  • Input the Deviation. A big number will make a large change to the polygons, removing many points. A smaller number will keep more vertices.
  • Click on the OK button.
  • The selected polygons will be simplified.


Import A 3D DXF/DWG

Importing a 3D DXF/DWG file is similar to importing a 2D file. When you choose the import options instead of choosing all 2D, choose all 3D. Then follow the same steps as you followed for the 2D importing. Remember to start with a completely blank file, calibrate the file after importing, and simplify the polygons.
The main difference is when you import a 3D DXF file, you will have several contours that you can use directly to create your site model. You can delete any of the information that you no longer need, but please retain all the 3D contours and spot levels that are at the correct elevation. In other words, you can delete all the lines that you don’t need and all the text that is no longer required.

Import A Shapefile (GIS Data)

When you import a shape file, you do not need to import these into a completely blank document. Shape files are normally three-dimensional polygons that have information attached to them. When you import a shape file with contours, you normally get the contours at the correct elevation and at the correct location.
Normally you will import shape files for large sites. This is where you can get contours that have thousands of vertices. Use the instructions from the 2D DXF/DWG file to simplify these polygons.
The result will be a series of 3D polygons that can be used to directly create the site model. If you find the polygons are in groups, ungroups then and ensure you choose the option on the dialog box to assign the data from the group to the polygons.
These polygons will also have a lot of vertices, so simplify the polygons using the same steps outlined above for the 2D polygons.

Intermediate Topics – Creating The Site Model Data

So far we have talked about importing data. We may need to convert the information from 2D to 3D in order to make the site model. Remember we need 3D loci, 3D polygons, NURBS, or stake objects to make a site model.

2D Contours To 3D Data

There is a command that will turn polygons into 3D data that we can use. This exercise will show you how to use that command. If you have a file with 3D information, you will not need this technique.
Before you use this technique you need to understand that this will convert all polygons on the selected layer. If you have other objects that you do not want to be converted, you will need to move these to a separate design layer for class that can be turned off. You should end up with just the polygons that will make the site model

  • Ensure that nothing is selected, and use the Attributes Palette to set the default values to the have no fill and a heavy line.
  • Go to the Basic tool palette. Choose the 2D Polygon tool. You must use the Polygon tool for this, do not use the Polyline tool.
  • Go to the Tool bar. Click on the first mode.
  • Go to the Snapping palette. Turn off all the snaps.
  • Zoom into the plan. Start at the lowest contour and work methodically until you get to the highest contour.
  • The contours must be evenly spaced, e.g. every foot or every meter. You might have to zoom in more, to see enough of the contour.
  • Start outside of the site. Try to line up with the existing contour line. We need data outside the site, this is how you can add it.
  • Click once. Click along the contour.
  • When you finish, remember to finish outside of the site.


  • Trace over the next contour.
  • Remember to start outside of the site and finish beyond the edge of the site. You will have to use the existing contour as a guide for the placement.
  • Do the same for all the contours.


  • Go to the Menu Bar.
  • If you are using Landmark, choose Landmark > Survey Input > 2D Polys to 3D Source Data…
  • If you are using Architect or Designer, choose AEC > Survey Input >2D Polys to 3D Source Data…


  • This dialog box opens. We set the height of the first contour and the interval (or height) between the contours.
  • Type in the Start Elevation.
  • Type in the Interval.
  • Choose Create 3D Loci.
  • Click on the OK button.


  • Vectorworks selects the first contour that you drew. Vectorworks uses the order you drew the contours in to select each polygon. Hence, it is very important to have drawn these contours in the correct order.


  • Click on the Next button.
  • Vectorworks selects the next contour.
  • Click on the Next button.
  • Keep going until you reach the end.
  • Click on the Next button.
  • Click on the Yes button. We do not need to keep these polygons. They have done their job.


  • Now you are left with many 3D Loci. They can be used to create the Site Model. You might also notice that there were missing contours at the top part of the site. Because there were no contours, we have no spot levels, and we will not get a complete Site Model.


Stake Objects For Site Model

You can use the Stake object, or 3D loci to create additional data for the Site Model. This is useful for placing points that match the survey information.

  • Go to the Site Planning tool set and click on the Stake Object.
  • Go to the Tool bar and set your Preferences.
  • Set the mode to Include as Site Model Data and choose the Style to suit.
  • Use the Standard Insertion Mode.


  • Move your cursor to snap on a spot level, if you are using an imported survey. If you are working with a PDF file, you might be able to snap to the spot levels; however, if you have imported a scanned image, you won’t be able to.
  • Double click to place a Stake Object.
  • Go to the Object Info palette.
  • Enter the Elevation (Z value).
  • The stake object will show you the elevation, if you have set your Preferences set accordingly.
  • There is an area to input the elevation of the stake object before you click. You only need to click once to place a Stake (which I think is a real time-saver).
  • Input the elevation of the spot level on the Tool bar.


  • Move your cursor to a spot level.
  • Click once. This will place your stake object.
  • Place several stake objects.


Importing Survey Data

You can import data from a surveyor. The data needs to be provided in the correct format. The data can include the point number, and it has to include the X-direction (Easting), the Y-direction (Northing), and the Elevation.
The file has to be a text document, not an Excel spreadsheet.
Notice whether the first line has data on it. If the first line has titles, open the file in a text editor and remove the first line.

  • Go to the Menu Bar
  • If you are using Landmark, choose Landmark > Survey Input > Import Survey File… If you are using Architect or Designer, choose AEC > Survey Input > Import Survey File…
  • Locate the survey file.
  • Click on the Open or OK button.
  • Choose the options for the Eastings and Northings that match your file. Set your options for the units in the survey file.
  • Click on the OK button.
  • As Vectorworks imports each line of data, it creates a Stake Object or 3D Loci (depending on the setting that you chose). These will be used to make the Site Model.


Creating The Site Model

A Site Model is created from 3D Loci, 3D Polygons, NURBS curves, or Stake Objects. You can use any of these types or you can use a combination of these.

  • Select your source objects (3D Loci, Stakes or 3D Polygons).
  • If you are using Landmark, then go to the Menu Bar.
  • Choose Landmark > Create Site Model…


  • If you are using Architect, then go to the Menu Bar.
  • Choose AEC > Terrain > Create Site Model…
  • Set the options for the minor contour interval. This is the vertical height between the minor contours. The major multiplier is how many minor contours are there for each major contour.


  • Choose the settings for the 2D Display. You can choose to show the existing model, the proposed model, or both.
  • Choose the options for the Style of the Site Model. Traditionally, users choose 2D Contour (smoothed), but that is not the only choice. The other settings might also be useful. Try them to see what they do.


  • Choose the settings for the 3D Display. You can choose to show the existing model or the proposed model, but not both.
  • Choose the options for the Style of the Site Model. Try the settings to see what the options are.


  • Check all your settings.
  • Click on Graphic Properties… button.
  • You can edit the graphic style of the parts of the Site Model.
  • You can set the graphic properties of parts of the Site Model to suit your drawing style.
  • You should use classes to control the graphic style of the parts. This will allow you to change the graphic style later (or in viewports).


  • Click on the OK button again to close the Graphic Properties dialog box.
  • Click on the OK button once more to close the Create Site Model dialog box.
  • Here is the Site Model.


Advanced Topics


Reshaping The Site Model

The Site Model crop is a polygon that stretches around the information you have supplied to Vectorworks. The Site Model crop works a lot like the crop in the viewport. It can also be edited to filter out information that you do not want to show. The Reshape tool can be used to edit the crop around the site model and to edit the labels on the contours.

  • Select the Site Model.
  • The orange line surrounding the Site Model is the Site Model crop.
  • Go to the Basic tool set.
  • Click on the Reshape Tool.
  • Go to the Tool bar.
  • Click on the first mode, the Edit Site Model Crop Mode.


  • When you select this mode, you will notice that you get a blue handle at each vertex of the Site Model crop, as well as a blue handle at the midpoint between each vertex.


  • Go back to the Tool bar.
  • The second group of modes is for choosing how you want to deal with each vertex. You can move the vertices, change vertex types, add vertices, or remove vertices. In this example, I am going to show you how to remove vertices, so I have selected the Delete Vertex Mode.
  • To delete a vertex, move to the vertex that you want to remove. The cursor will change shape to a minus sign and an arrow.
  • Click once to remove this vertex.
  • Move to the next vertex that is not required and repeat the process.
  • Keep removing all the vertices that are not required.
  • Return to the Tool bar and change to any of the other modes required, the Move Handles Mode for example .
  • Move the corner vertices of your Site Model crop to reshape your Site Model to suit your project.


  • The Site Model has labels on each major contour that can be edited with the Reshape tool.
  • Select the Site Model.
  • Go to the Basic tool set and click on the Reshape tool.
  • Go to the Tool bar and click on the second mode, the Edit Site Model Label Position Mode.
  • When you select this mode, you will notice that you get a blue handle at each label.


  • Go back to the Tool bar.
  • The second group of modes is for choosing how you want to deal with each label. You can move, add, or delete labels.
  • Click on the handle in the center of a label. Notice that the cursor changes shape.
  • Move along the contour line. You can only add or move labels on the major contour lines.
  • Click once to position the label.
  • Go back to the Tool bar and click on the Add Label Mode.
  • Move along the contour line.
  • The contour line will highlight. You can only add labels to major contour lines.
  • Add labels to all the required contours
  • Use the Delete Label Mode to remove labels


  • Add, remove, and move labels to suit your design.


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