Semi-Outdoor Lighting

by Montree T. (easyyong@hotmail.com) - Smoke3dStudio  


The semi-outdoor lighting uses a similar technique to the interior lighting in my previous tutorial. The semi-outdoor is slightly different in that the opening is bigger and divided by columns.

1. Creating a main ambient light

I use 1 brown/grey omni, ambient only, placing it in the middle of the interior and the start of the far attenuation is fit to the room.




2. Creating sub-ambient light

Put light blue omnis, ambient only, in the openings between the columns. The start of the far attenuation is also fit to the opening. The sub-ambient blue color is a skylight ambient which scattered around the area.




3. Creating specular and diffuse passes and soft shadow

3.1 Creating skylight

Copy the skylight omnis and change ambient only to diffuse and specular. This is to create specular and diffuse pass of skylight that affect the scene.



The opening of a semi-outdoor scene is slightly different from an interior opening in that the opening is bigger and divided by columns. I put an omni as a skylight outside an opening/ window. This will also use same technique in that we consider an area between the columns as a big opening.

Tip: Shadow is affected by playing with the attenuation

3.1.1 The darker area in the highlight area on the picture is the area between start and end of the far attenuation.



3.1.2 Place omnis as a skylight, the start of far attenuation is fit to the area in between the columns, so the light in the area beyond that will be darker.



The picture above is a rendering without a main ambient. Only the skylight affects the scene.

3.1.3 The area between the start and end attenuation of each omni in the scene when intersected, will still be darker and look like column shadows. So with this effect, we sometimes don't need to make all the skylight cast shadows.



3.2 creating soft shadow

Place 2 direct lights up and down to ceiling and floor and make the shadow density negative and color to be grey. The hot spot and fall off of the lights will be fit to the building as well.




Now we can see the soft shadow of the chairs and another layer of soft shadow of columns.

4. Sunlight

Create a target direct light with raytrace or advanced raytrace shadows set to cast sharp-edge shadow directly from sun.




5. Sunlight illumination

The scene with large openings has direct sun illumination . I place omnis down to the floor at the same position of the sunlight on the floor to create bounced light which illuminates the area. I also want the light to affect some parts of the timber ceiling so I make the omni's attenuation touch the ceiling.