This tutorial explains how to use Ecotect to perform a spatial visibility analysis, which allows you to calculate the visibility of selected objects from different points in the model.
You will need about 15 minutes to complete this tutorial.
Training and Accreditation
Successfully completing this tutorial fulfills one of the practical skills required for completing Level 1 of the Visual Impact Analysis training module.
To complete this tutorial, open the Estate.eco file located in the the Examples folder of your Ecotect installation.
Configure the Analysis Grid
Before you can perform a visual impact analysis, you first need to configure the analysis grid, which is used to plot the level of visibility selected objects within the model.
- Using the Zone Management control panel, select all of the objects contained on the Roads zone. We will use this selection to set out the extents of the analysis grid.
Select the objects on the Roads zone.
- Go to the Analysis Grid control panel. Click the Auto-Fit Grid to Objects... button.
Click the Auto-Fit Grid to Objects button in the Analysis Grid control panel.
- The following dialogue box appears. Configure the settings as shown in the following screenshot, and then click Ok.
Configure the auto-fit grid as shown.
The analysis grid is now set up.
- Usings the Zone Management control panel, select all of the objects contained on the RedBuilding zone (yes, they are actually coloured green, but all will become apparent in a moment).
Select the green buildings.
- Go to the Calculate»Spatial Visibility Analysis...' menu item, and the following wizard appears. Select the Visibility of Selected Object(s) radio option and then click Next.
Start the Visibility Analysis Wizard.
- The next wizard screen confirms that you have selected objects to perform the visibility analysis with. Click Next to continue, or press F2 to return to the model to select additional objects. Press ESC to return to the wizard.
Confirm you have selected objects for the analysis.
- Specify the sampling grid size. If you're not sure what size to make the sampling grid, click the Suggest a Reasonable Sample Size button and then click Next.
Let Ecotect suggest a reasonable sample size.
- The wizard summarises the selections you have made for the visibility analysis. Make any changes if necessary, and then click Ok to proceed.
Confirm your selections, and then click Ok to proceed.
- Ecotect performs the visibility analysis. Depending on the speed of your computer, this may take a few minutes. When complete, the analysis looks something like the following screenshot :
Ecotect calculates the visibility analysis.
Interpreting the Results
- The legend in the top-right corner indicates what area of the selected objects are visible in relation to the analysis grid. This takes into account the view angle of each surface. Point and line objects do not contribute at all to this value.
- Note that selected objects that are being tested for visibility do not obscure other objects being tested - they are ignored in the ray-intersection calculation. This is important as it allows the user control over what the percentage values (discussed next) actually mean. However, if required, you can choose between the percentage of all objects or the percentage of only visible objects by toggling the Check Both Sides option in the wizard.
Use the Check Both Sides checkbox to control how selected objects affect visibility of other selected objects.
- Sometimes a percentage legend is visible in the bottom right corner of the screen. This represents the sum of the percentage of each object actually visible, without consideration of view angle.
- You can use the Analysis Grid control panel to control how the analysis grid is displayed, such as showing the grid as contours, or in 3D.
- Switch to the Visualise page for more options regarding the graphics display of the overall image. Note how the selected building displays as red under the Visualise page, hence the zone is named RedBuilding. Convoluted, I know.
Use the Visualise page for additional options for how the graphics are displayed.