A team of Harvard architectural design researchers wrote Diva so they could do daylight analysis inside Rhino.
A team of researchers at the Harvard University Graduate School of Design have released Diva, a plug-in for the popular 3D modeling software Rhino that allows for daylighting analysis without exporting a model out of Rhino.

When installed, Diva appears as an additional toolbar in Rhino. In use, it accesses free analysis tools on the web, allowing their calculation results to appear in Rhino.
Diva can generate radiation maps, visualizations, climate-based metrics, glare analysis and LEED IEQ Credit 8.1 compliance.
According to the developers, Diva was developed in order to use various web-based analysis tools inside the Rhino modeling environment, avoiding the necessity of exporting the Rhino model to Ecotect or other analysis software. The goal was to reduce the steps involved in validating daylight analysis, to make it more accessible, easier to use, and less likely to be compromised by user error.
Diva uses the following third party software:
To use Diva, a designer creates a model using standard Rhino modeling methods, then selects a surface or series of surfaces from which a grid of sensor nodes will be generated. The toolbar, which is displayed like other Rhino toolbars, can be used to setup and perform the analyses. The final results are either images generated in Radiance and displayed in a separate image viewer, or consist of a grid of false-colored panels with accompanying legends.

Diva was developed by Christoph Reinhart, Alstan Jakubiec, Kera Lagios and Jeff Niemasz at the the GSD-Squared research initiative at Harvard University’s Graduate School of Design. It can be downloaded for no charge at the Diva-for-Rhino website.
DF says
Actually they are not web based. Web based would require you to be online during the analysis, this is not correct. Basically from what I understand diva exports( this is when u see the cmd screen working/ dos) the rhino geometry into a rad file that automatically begins calculating using radiance and daysim to measure daylight levels. The values are then automatically imported back into rhino for a visual display of the results.
Df says
Radiance is the industry standard backward raytracer used for calculating daylight simulations. It is typically used to measure daylight levels for a certain point in time, such as sept 21(as required in LEED IEQ. 8.1) Both Ecotect and ies virtual environment are capable of using radiance for higher accuracy simulations.
Daysim is used to calculate daylight autunmy. Which measure the percentage of light for the entire year.
So this diva plugin is actually really cool. It’s going to be awesome to see how this plugin evolves