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Part 1 : I Have Seen The Light

Firstly let me start off with a few warnings, not about Poser 6, but about the information that follows.

LIGHT TYPES

Poser allows you to create four types of lights: infinite, point, spot and image based.

INFINITE LIGHTS

Infinite lights are comparable to the sun or moon shining on the Earth. Rays from infinite lights are parallel as they enter your Poser workspace. If you have multiple figures and/or props in your scene, infinite lights shine on each item equally. You cannot place any scene element beyond an infinite light’s range, and no figure/prop can be lit differently than another.

POINT LIGHTS

Point lights are similar to a lightbulb, in that they emit light from a single source point outward in 360 degrees. These lights are ideal for times when you want an omnidirectional light source that can interact with objects and cast shadows in ways that an infinite light cannot. For performance reasons depth mapped shadows are not supported for point lights; point light shadows must be calculated using raytracing.

SPOTLIGHTS

Spotlights cast light in a specific direction, throwing light along a cone-shaped path to create a classic stage spot effect. These lights are useful for illuminating specific objects or for creating lighting effects. Spotlights can increase rendering times.

DIFFUSE IMAGE BASED LIGHTS (IBL)

Diffuse Image Based Lighting (Diffuse IBL) takes a light probe, which is ideally a 360 degree light distribution captured in a single 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 are very realistic. In order to get realistic shadows when using an image based light, we recommend using Ambient Occlusion (see “Light Properties“ on page 130). You must activate raytracing in the Render Settings window in order to render Ambient Occlusion effects. To attach a light probe to the image based light, press the Advanced Material Properties button on the Properties palette. Once in the Material room, you have the option of attaching simply a light probe image map, or a shader tree of any complexity, to the color channel of your Diffuse IBL.


OK, so what does that all mean in relation to what you see when you hit the render button?
Let's take Point Lights first, and compare the Point Light to it's closest neighbour, and the light you're probably the most familiar with, the Global light.

Here's a simple scene rendered with one Global light. The scene setup is a hand, holding a “six“, in front of a white square...

And here's the same scene using a Point light in place of the Global light...

Although the shadows are now falling much more naturally they're still really harsh so lets set the light's shadow value down to 0.5 for the next render, and the Shadow Blur Radius to 2.0...

Now we're going to make use of another new trick Poser 6 has up its sleeve, Ambient Occlusion, or AO.
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.

Here's our third render again, but with AO added to the Point Light this time. It's very clear how the AO has darkened the area inside the loop of our “six“ but look more closely and you'll see some more subtle areas it's worked on.

Now let's look at all four renders together, and see how much they differ.

Global Lighting

Point Lighting

Softer shadowed Point Lighting

Softer shadowed Point Lighting + AO

As you can see, the first image looks pretty bland, while the second image although more naturally lit still has harsh shadowing. By image 3 our render is really starting to look good, with the shadows now softened and by adding AO to render 4 we get even more natural shadowing to compliment the lighting type we've settled on.
Of course, if I were rendering this image “for real“ I'd play with the light positioning from render to render, but in the above images I've the kept the light in exactly the same place to compare the way the image changes more realistically.

Paul Salmons aka slinger
For PlanIT 3D © 2005