Daylight Visualization & Radiation Maps for DIVA: Urban Design and Development

This tutorial is written for Rhino 5.0+ (Windows) and DIVA 2.0+, and assumes you have Rhino & DIVA installed.

Written by Elliot Olney (olney005@umn.edu).

General Information about Daylight Visualization & Radiation Maps:

Daylight Visualization:

• The Visualization simulation creates a Radiance rendering of the selected Rhino view of your model. This is a useful simulation to run before all other simulations, because it provides very useful information as to whether your model geometry is defined correctly and properly exporting. Sometimes surface normals are flipped, geometry is turned off or has not been defined a material, or other inconsistencies occur. The visual check allows you to preview the model the way Radiance sees it before running your simulation. Make sure your selected viewport is a perspective view and not an orthographic projection.

Radiation Maps:

• DIVA for Rhino can generate climate-specific annual surface irradiation images or calculate annual irradiation at node locations. This is a powerful tool that can be used on an urban or building scale to identify locations with solar energy conversion potential or areas in need of shading due to excessive solar exposure. Comparing summer and winter period irradiation results could help optimize shading devices to maximize winter gain while minimizing summer exposure.

DIVA Resources:

DIVA for Rhino User Guide

Radiance Reference Guide - Radiance is the rendering engine that DIVA utilizes to visualize the data it calculates.

• • Advanced Settings Options for Radiance - note: These were used for this tutorial.

STEP 1 - Getting Started:

Begin by downloading the diva-viz-and-radiation.3dm, located at the bottom of the page, and open it in Rhino 5.0+

• • Once the model is loaded the first step will be to set your Location, click the DIVA toolbar where it says "Location", and choose where you would like to conduct your study.

  • Next, assign Materials to your scene, click the DIVA toolbar where it says "Materials" and select "Assign Materials" from the drop-down menu.

    • In the DIVA Assign Materials window make sure you are under the "Daylighting Materials" tab, and choose the materials as follows:

• • • Click "Submit Material Information" - note: If you are using your own file, you may have more layers, or none and need to organize your geometry on layers.

STEP 2 - Run your First Daylight Simulation:

Lets start by running a Daylight Simulation without placing the building we want to study. This will give us a reference point for our placement and will help us become familiar with the DIVA settings and controls.

NORTH IS IN THE POSITIVE Y DIRECTION.

• • Use the following settings for your first simulation, then click "Run Simulation":

• • The only setting in this screen you need to be concerned with is the "Date and Time."

  • Results:

• • Image #1: March 21 - 9am Image #2: June 21 - 9am Image #3: September 21 - 9am Image #4: December 21 - 9am

STEP 3 - Adding your Building:

For this tutorial I will be looking at the effects of a new multi-use building and park adjacent on the western edge to a downtown stadium.

• Here is my new "building" placed in the empty lot, with the park equally surround the perimeter:

• • Image: December 21 - 9am

  • I am not happy with how the shadows are consuming much of the site, lets move the building now that we are informed of its impact on the surround environment.

• Here is the new placement of my building:

• • Image: December 21 - 9am

  • The site has much better access to sunlight now that the building has moved.

STEP 4 - Radiation Study for the Proposed Massing:

For this simulation we are going to look at the solar gain on our proposed building and site for optimal placement of the proposed site.

• • Here are the settings you should use to run this simulation:

• • • The start time and end time should be in a six month period, so you can study the Winter and Summer conditions on your building. Hour range should be left the at the default of 00 24.

    • Under the advanced parameters I have changed the Radiance Parameters from the defaults as follows:

      • DEFAULT: -ab 2 -ad 1000 -as 20 -ar 300 -aa 0.1

      • CHANGED TO: -ab 2 -ad 512 -as 256 -ar 128 -aa 0.15

      • Advanced Settings Options for Radiance - Descriptions of what each setting can do. I made changes to increase the speed and quality of the rendered simulations.

• • Results of the winter simulation:

• • Results of the summer simulation:

• • From these results we can tell that there is still some optimization of our building location to be done, particularly for the winter months.

  • Final building placement results, winter simulation:

• • Turning the building 90 degrees allows for more solar gain during the winter months.

CONCLUSION:

Using these quick and easy tools can help push a design forward in the early stages of development.