I'm a lighting designer and have been looking into software that links directly with sketchup to help me with lighting designs; rather than having to export models to other lighting programs. LightUp looks really great; but the one thing that I'm concerned about is that there seems to be no inter-reflection calculations in the renders. (i.e. calculating how much light reflects off walls and ceiling to contribute to the overall light level in the scene - using, say, radiosity techniques). This reflected light can be very significant and can in circumstances double the amount of light that falls on a desk; particularly if there highly reflective walls near by (e.g. painted white) with quite omni light sources.
In the hand calcs highlighted previously in this tutorial, this is where the UT (ulitlisation factor) plays its part (which assumed a 70% ceiling, 50% walls and 20% reflective floor). admittedly, when considering a large open rooms, the contribution from walls is not so significant.
Am I right in thinking LightUp does not consider inter-reflections and only considers direct light when calculating lux levels?
Explanations, Walk through, tips and techniques related to LightUp