JAG opened this issue on Jun 26, 2014 ยท 21 posts
bagginsbill posted Fri, 27 June 2014 at 6:53 AM
Vilters this isn't true, either.
I know you mean to help, but much misunderstanding, including what seems like good advice, has been twisted into hard and fast rules that don't take into account all the factors. (Please note, the advice may even have been given by me several years ago. If I did, it was because I did not understand physical rendering yet, and how far from it Poser is. I now suggest that specular nodes have to be programmed much brighter than earlier thought.)
I routinely set up my Blinn node with a reflectivity of 90 - n i n e t y - which clearly violates the "can not be higher than 1" rule, but that's because the rule is not being stated accurately in that way.
In the attached image, every pawn has a specular node set up with a value higher than 1 - in fact the numbers vary from 22 to 90. What is wrong with these? Nothing - they are defining the size and brightness of my virtual light bulb, which as you know (I hope) has no dimension at all. Poser lights have no visible effect in and of themselves. We know they exist only through the behavior of our various lighting nodes. How those nodes "pretend" what size the light has is something we control. How those nodes "pretend" about the brightness of the light is also something we control. Two objects can appear to be reacting to different virtual light bulbs because the light has no property of size, just brightness. The apparent size and brightness of the light source is ultimately defined by the material reflecting that light source.
So - it is not accurate to say that the sum of diffuse and specular must not exceed 1.
What is accurate is that the amount of light reflected from a surface cannot exceed the amount that arrives. But we're very unclear in Poser about how much has arrived. It's not a physical model.
It is accurate to say that the sum of your Reflect + Diffuse node cannot be more than 1. !!!
Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)