Kultivate Arts

If you’re a Second Life photographer, you probably want your photographs to look as “real” as possible. There are several things you can do to give you photos a greater sense of realism, and I hope to cover as many of these as possible in these posts.

One of the easiest things you can do to add a little more realism to your photos is turn on Ambient Occlusion.

What is Ambient Occlusion?

Ambient Occlusion is an effect that attempts to simulate realistic shading around objects. It does this by trying to take into account the ambient light obstructed, i.e. occluded, by objects in a scene.

A scene without ambient occlusion can look flat, lacking a sense of depth, and shadows will appear sharp, jagged, and have a uniform tone.

Second Life uses a form of AO called Screen Space Ambient Occlusion (SSAO).  SSAO is somewhat old tech, and the movement in the gaming industry is towards what is called Horizontal Based Ambient Occlusion (HBAO). There’s more info on HBAO on the NVIDIA site.

Enabling AO

You can enable AO in three different places in your FS viewer:

1. Under the Developer menu (Ctrl-Alt-Q.): Developer – Rendering – Advanced Lighting Model (Has to be checked; AO doesn’t work without ALM on.). Select SSAO and Shadow Smoothing.
2. Under you Preferences (Ctrl-P): Preference – Graphics. Check Ambient Occlusion under Shaders.
3. Phototools (Alt-P.): On the Light tab, under Ambient Occlusion Settings, check Enable Ambient Occlusion (Depth Perception)*.

I just use Phototools. It’s faster.

*Based on the definition of Ambient Occlusion being more about producing realistic shading, “Depth Perception” is not the best way to think about AO.

Ambient Occlusion settings

Phototools provides 5 different settings for tweaking the way AO influences your photos. I’ve listed these below with a brief description quoted from the Phototools tool tips (You can see the complete tool tips in world. Just hover your mouse over the appropriate word.)

• Scale – “Controls sampling region; larger regions are more accurate.”
• Max Scale – “Controls maximum screen radius from which to sample from…”
• Factor – “Scaling factor for the effect…”
• Effect – “Controls the overall darkening effect of Ambient Occlusion.”
• AO soften – “Controls the softening of the Ambient Occlusion effect.”

Does that seem confusing? It is. The best way to understand all of these settings is to play with them in world. I’ll try to show you what they do in a follow-up post.

Style thoughts

Ambient Occlusion is a useful tool for adding realistic shading effects to your photos. Turning it on, usually improves the quality of your photos.

Keep in mind though, AO simulates shading effects. Sometimes this simulation adds some “noise” to your photo and no one wants noise in their photos. If you’re getting noise from AO, try changing your camera angle or simply turn it off.

Your AO effects are influenced by the Windlight you’re using, too. In particular, the position of your sun or moon will greatly impact the apparent effects of AO. If the sun is directly overhead and shadows are washed out, enabling your AO is going to have less of an effect.

[Tip: Sometimes you can get some very stark shadows without AO. AO makes shadows more “realistic”, but you might not want that.]

I find AO is useful in almost any photo situation, whether it’s a photo with a lot of depth or one in an small, enclosed space. But remember AO is another tool. Use it when you need it, but if it’s not needed or seems to be “making noise” don’t use it.