Christoph Reinhart (currently with Harvard and formally with the NRC-IRC) and our very own Pierre-Felix Breton have led an effort to test the simulation results from 3ds Max Design 2009 Exposure against actual physical measurements and against the results of Daysim 3.0 (which is based on the Radiance engine - as are most lighting analysis programs). Today, most experts use Radiance-based programs for lighting analysis because of the work that Christoph did on validating Radiance with physical measurements. The original paper can be found at the linke below:

When we designed the new Exposure feature for 3ds Max Design, we knew that people would soon be asking us if it was accurate, so we embarked on an effort with Christoph to figure this out. After a lot of work and simulations, we got the results we were hoping for, the "accuracy of both programs is sufficient for typical daylighting design investigations". This means that 3ds Max Design is one of the few products to have been independently validated by the same team that validated Radiance and joins a rare group of products that generate equivalent results to Radiance.

Here's the abstract:
"This report compares daylight simulation results generated with two simulation programs, ‘Autodesk® 3ds Max® Design 2009’ (3ds Max Design) and Daysim3.0 (Daysim), to real indoor illuminance measurements in a sidelit space. The sidelit space was in a single location, but was configured with five fenestration and glazing options, and operated under a variety of sky conditions. The measurements form a set of ‘daylighting test cases’ that were recently developed to evaluate the simulation capabilities and limitations of different daylight simulation programs. Both simulation programs were given external direct and diffuse irradiances as simulation input, from which they had to predict indoor illuminances on a grid of upward facing work plane sensors and downward facing ceiling sensors.

3ds Max Design is based on ExposureTM technology, a lighting analysis module that includes a ‘shader’ of the Perez sky model and that uses the mental ray® raytracer for the global illumination calculation. Daysim also uses the Perez sky model and is based on the Radiance backward raytracer combined with a daylight coefficient approach. The comparison of both programs with measurements demonstrated that 3ds Max Design simulated indoor illuminances for the daylighting test cases with reliability comparable to Daysim. Most mean bias errors and root mean square errors were in the range of those reported in earlier validation studies: both programs succeeded in reproducing measurements for a sidelit space with and without a lightshelf. While 3ds Max Design consistently underestimated the incoming light flux going through a translucent panel, Daysim results were lower than measurements for the internal venetian blind test case. The results suggest that the accuracy of both programs is sufficient for typical daylighting design investigations of spaces with complexity comparable to the five daylighting test cases."