Lighting design (Indigo vs Radiance)

[motorsep]

I found a renderer called Radiance (http://radsite.lbl.gov/radiance/refer/long.html)
and it states that it was designed to simulate real life lighting accurately, so designers/architects can determine how many lamps, what type of lamps and what wattage they have to use to get lighting right in certain space.
Is it possible with Indigo to get same or about the same accurate (thought not precise) results?
I mean when I design a room and I have certain size windows and I render with Indigo day light scene, will it be accurate enough to say: "There ya go, with windows that big and on sunny day, that's how your room is going to be lighted."
As for artificial lighting, is there a way to define values of real light sources, like Watts for light bulbs, type of lights (fluorescent or regular, etc.)or use IES standards in Indigo?
I am asking that because there have been cases when render looks awesome, but when design has been turned to life, lighting in it looked very different.
Thanks.

[joegiampaoli]

This has been discussed before, maybe Nick will implement it

http://www2.indigorenderer.com/joomla/f ... c.php?t=33

[Wedge]

I would guess that no matter how good of a program it is...you probably cannot determine all the necessary factors for figuring out exactly what the lighting setup will look like in real life.

I mean, wouldn't glossy paint type alter how much light is bounced?

How about a carpet floor, does it absorb more light than a glossy wood floor, or maybe a white tile floor?

Is the ceiling glossy painted or textured?

How about type of light bulb, I recently bought a light bulb that is bumby and casts a 'flame like' light onto the walls? (like caustics from a water bottle, hard to explain)

It seems mostly the materials that cover much of a house, would change the way light worked its way around the most.

How about tone mapping...what would simulate an accurate setup with the lights that are used? Can we simulate time of day how light is coming through windows? (clear or cloudy day, how about a snowy climate, can we simulate that intense blue/white glow coming in the windows?)

Is it possible to make it reasonable enough so that it was accurate enough? I don't know. I will stop here because I don't know what I'm talking about and only have added questions into the mix.

[F.ip2]

I guess here the trained artist eye has to kick in to tweak values in a way that your rendering represents what you want to see!

[joegiampaoli]

Materials and colors play a very important role in architectural lighting, Autodesk Lightsacpe did part of the calculations with this information, as a matter of fact it was based on radiance's rendering algorithm (not only raytracing but raybouncing by creating shading grids on other surfaces where indirect light was bounced). Also every light fixture has its own photometric data (ies), which is how intense, angle and shape the light shoots out of the fixture.

So yes, a glaze material will reflect light more different than a flat surface, and depending of the surface colour also.

For those who want to achieve good lighting calculations (but not very good renders), this is for me probably the best lighting analysis software, it only runs on windows but it's free....

http://www.dialux.com/e/index4.html

EDIT: will output nice PDF's with lighting fixture positions, isocurves with light intensity, fixture info, how many lumens, luxes candelas, etc.....