Forum: Poser - OFFICIAL


Subject: Newbie Question: P6 - AO, IBL, Shadow Catcher.. Whats that?

Eismaus opened this issue on Mar 25, 2005 ยท 9 posts


slinger posted Fri, 25 March 2005 at 10:20 AM

Attached Link: http://www.planit3d.com

AO = Ambient Occlusion AO makes figures and objects appear as though they are in a natural lighting environment, thus providing a new degree of realism. AO darkens surfaces within a scene whose exposure to light is blocked by other objects. This effect uses raytracing to calculate the degree to which other objects within a scene occlude the ambient light of a surface at a given point. Surfaces with more occlusion will be rendered as darker than surfaces with little or no occlusion. Just to remind you, all the images we're using here have their shadows raytraced in Firefly. Some features (like Point Lighting) can't use the old Depth Mapped Shadows so we couldn't compare the various iamges fairly if we mixed them up.

IBL = Image Based Lighting
Diffuse Image Based Lighting (Diffuse IBL) takes a light probe, which is ideally a 360 degree light distribution captured in a single image map, and illuminates the scene using that map. In Poser, only the diffuse component of the light is defined by the light probe. As this technique is based on complete light data for a given space, the lighting results can be very realistic. In order to get realistic shadows when using an image based light use Ambient Occlusion.

NOTE: For ambient occlusion to work you must set the shadows to Raytrace on your light(s)

The Shadow Catcher...
...allows transparent surfaces to catch shadows, as opposed to letting the shadows appear on the opaque surface behind them. In other words, this option will treat transparent surfaces as opaque, only in terms of their interaction with shadows. A prime use of this feature would be if you wish to render only a figure and its shadow; you could set up the floor as a transparent surface by using the ShadowCatchOnly feature to show your figures shadow on the transparent floor, and render (without the background). The floor will be invisible except for the shadow laying on it, so the only things in your rendered scene will be the figure and its shadow.

You can check out some examples and mini-tuts on all of these (and more) in our Tutorials forum over at PlanIt 3D
[edited to admit to being a day late and a dollar short thanks to Nerd ~lol~]

Message edited on: 03/25/2005 10:21

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