ruff rules of thumb that are coming in a new tute on lighting in Bryce that I've been working on for about 6 months now. These assume clear/hazeless/fogless settings: Squared light ranges: power 25---------250 BU power 50---------300 BU power 75---------350 BU power100---------400 BU power125---------450 BU power150---------500 BU power275---------550 BU power300---------600 BU what does this mean? well for squared Bryce simulates the real world lighting effect of say lightbulbs. For every said distance away from the source, the power drops by a square. Bryce does not do it exactly, in fact..its rather cheezy how it works. It acually renders ranges of the light at the same intensity (most have 5-10 falloff zones..for this example Im gonna use 5 for all) So if you look at the above...if your light is at 50 (it has a range of approx 300 BU), then objects between 1-60 bu from the light will be 100% lit, if its at 61-120 bu it will be 50% lit, if its at 121-180 bu it will be 25% lit and so on... (like I said, bryce doesnt do the as the real world would, but its better than linear) Linear light ranges: multiply the power setting by 100 this will give approx BU. this is supposedly a linear falloff of lighting...it again uses ranges however. for linear light of power 50 (it has an approx range of 5000) at 1-500 bu the objects would be 100% lit, at 501-1000 bu the objects would be 80% lit, at 1001-1500 the object would be 60% lit...etc... again this is just an example of how it is handled. The actual interpretation is much more involved and has more falloff ranges, is atmosphere dependant and material dependant, but the above should help a little in understanding what the numbers do... the tute wont be done for quite some time yet (some people havent finished portions of it, and others "jumped ship"..glances a clay..which took a little of the punch out of it) hope that all made sense and helped at least a little.. BT http://www.brycetech.com/