Urban Daylight v.01 Beta allows designers to simulate and evaluate the daylight potential of urban master plan proposals. In a two-step workflow, hourly solar radiation levels on all facades within an urban scene are simulated (Daysim) and then translated into hourly interior illuminance distributions using a generalized impulse response. Climate based day-lighting metrics, such as “Daylight Autonomy”, and “Spatial Daylight Autonomy” that are required for LEED, are also computed.

This novel approach introduces a method that is up to 100 times faster than the standard Daysim/Radiance approach. Additionally, the workflow is streamlined and the model setup is fully automated to make large architectural models manageable. For the first time, it becomes possible to evaluate the daylight potential of urban designs within a feasible amount of time. The hourly results and the satisfactory precision of 7-18% for the interior illuminace and 3.8 – 10% for the climate based metrics allow us to study urban designs in great detail easily.


McNeel Rhino 5 must be installed. If you would like to use the Grasshopper component McNeel Grasshopper for Rhino 5 has to be installed as well.


Urban Daylight can be downloaded form

Run the installer “UD_setup.exe”. The installer will create a folder under your “C:” drive called UD. The folder should have the following content.

The files highlighted by box “1” are the Grasshopper components. Place these files into your Grasshopper add-ons folder. You can navigate to that folder by launching Grasshopper. Click on: File->Special Folders->Components Folder

Cut and paste the files from box “1” into this folder.
In order to install the Rhino plug-in you have to drag and drop the files in box “2“ into a Rhino viewport.

After the Installation

After installing the Rhino plug-in and the Grasshopper plug-in you should see the UrbanDaylight tool-bars.

Rhino Toolbar

Grasshopper Toolbar

Next: Example File

In Short

Umi is a Rhino-based design environment for architects and urban planners interested in modeling the environmental performance of neighborhoods and cities with respect to operational and embodied energy use, walkability and daylighting potential. Since 2012, Umi has been  developed by the Sustainable Design Lab at the Massachusetts Institute of Technology with support from a National Science Foundation EFRI_SEED project, the MIT Energy Initiative, the Kuwait-MIT Center, the Center for Complex Engineering Systems (CCES) at KACST and MIT, Transsolar Climate Engineering and United Technologies Corporation. Further tool developed is now also being conducted at the Environmental Systems Lab at Cornell University.

A first public version of Umi was released during a public symposium on Sustainable Urban Design on May 6th 2013 at the Massachusetts Institute of Technology. Version 2.0, which also includes an embodied energy module, was released on November 7th 2014.

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