One of my on-going frustrations with ArchiCAD is their OBJECTS. I have not been able to find a reference quide to what each line means, how it can be changed, what are the limits etc. (ie. in photo rendering sun can be more than 100% ?). Attached please note that a double hung window is somehow not correct but there is no way for this architect (not a programer) and figure out what is wrong and why. The criteria in the window is not what this American Architect would ever organize his window as or with (eastern Europe must be different but...?). I look forward to learning where I can learn more to better use these integral parts of ArchiCAD. SOON !
Well, I can't help you with your frustration, but I can explain about the sun power.
In ArchiCAD 10, they finally have it adjusted correctly.
If you set the PhotoRendering Setting Sun to 100% and the ArchiCAD Built-in Sun Power to 100, and ambient to 100 in both, you SHOULD get a correctly exposed rendering.
Additional factors that affect these reliable settings - for scenes of "nominal" reflectance - include the magical "Undersun", additional energy from a SkyObject, and other light sources.
What you need for scenes of low reflectance or narrow windows and such, is , once you've put the sun to 100 in the Sun Dialog and it lacks brightness, you use the Multiplication factor provided by increasing that figure beyond 100 %.
After LightWorks in ArchiCAD was published, I went on the road and gave a seminar around a few places. The sun power thing was very confusing to many. I've included a few paragraphs that clarify the dialog box relationships in the upcoming ArchiCAD 10 supplement to my book, available only to registered owners of "LightWorks in ArchiCAD."
Attached is a basic rendering with ArchiCAD and LightWorks set to the 100 values throughout. with soft shadows from a realistic sun.
You'll see the shaded boards near the soffit are a bit "Crumbly." This is due to inadequate samples.