Forum: Poser - OFFICIAL


Subject: Capture the sky and sun light with |||||| Poser6 |||||| mini Tutor :)

Mec4D opened this issue on Jun 16, 2005 ยท 100 posts


jrabbit posted Sat, 18 June 2005 at 8:46 PM

O.K. Paul , here is a render as per your method. As you can see it does make it as if the light comes from the side like I have said 5 times now. Not the back. And as I keep telling you the color of the light becomes out of phase now with the background. Making the backgroung colors mud and destroying proper highlights spec ect. Caths chart of IBL is a "front" light set because the center of the chart = white. You know this already but some dont so they dont understand the differance. So it works perfectly to show how IBL complements the back ground and all is as it should be with face front light. That is what I have been showing. For a front lit scene Cath is 100% correct. In post 57 we are shown why we think we need your tut and the problem with a cloudy but seemingly sun lit back ground. Opps caths IBL map fails so some say. There are several ways to fix the problem as well as a correct explination why it fails. But I dont think Cath was done before she got interupted. Your method on a glance looks good but in fact is totally wrong. You forget or ignore that IBL contains color values and is additive in effect to color. And so it falls apart in serious work. There are several correct and better ways to keep the light in phase on all components and create the illusion of light from behind. The most professional is to make the IBL map from the 180 degree opposite section on the panoramic back ground image because it contains the right light data (color components and light values) for the back light effect. If it where an actual pano with the sun showing at one point. But this is not always possible as in cloudy pano's where we have several point lights breaking cloud that will cause that front highlight you hate so much. Thats when a second IBL back light can correct(dark centered IBL). No flipping no rotating no scripts needed. IBL, image based lighting favours front light for detail. As the IBL data is gathered from the direction the IBL was taken in not the back ! its a light probe not a dark probe LOL :) this is why rotating and flipping fail in detail color and light info , its a bad fake. For example the photo I showed in post 90 would make a great IBL for front of that "scene" but 5 feet behind me 180 degrees is a big blue wall. The reflection of the house can be seen on the sphere. If we rotate and flip that deal it wont mimic the real environment nor will the color and light data work properly because this front image has taken even unseen data into itself. I really would like Cath to finish HER TUT , caths way. But because you brought up your idea I cannot resist but point out its main flaw as to realizm and why its wrong. Try a jungle scene back ground with sun behind using your method with just a sphere on the ground . This is not yours or my thread or the place for us to banter. And I don't want to continue to trample Caths thread as we are being rude. If you want to move this to another new thread I will certainly as time permits provide more clear detail. We can rant and chant for 500 pages more. Jrabbit