How to light up a scene for a rendering is important. The basic knowledge of pencil sketching, the relationship of lights and the material's reflection behaviour matters a lot to render a good image.
For basic rendering knowledge to be shared here:-
1. Global illumination acts as a skylight to lighten the entire scene.
2. Sun light as a key light casting shadow towards a building to emphasize the form while determining the sun direction.
3. Ambient lights as general lights to cast shadow caused by skylight. It's role to be fill light as well.
4. Internal lights to lit up the internal spaces. Where it can be added through touched up in Photoshop brush effect too.
In scanline rendering, lights are articulated through the knowledge of lighting relationships.
In Vray rendering engine, it is much simpler to generate Global illumination through HDRI, where the lightest and the darkest point of light to be simulated through HDRI for external scene. It is much more expansive to render an internal scene as it depends more on light bouncing that requires more calculations and considerations on light settings.
3 point lighting is basic to be implemented throughout lighting an exterior scene. The proportion of Key light, Fill light and back light to stimulate the gesture of the rendered scene is important. Normal key to fill proportion would be 1:4.
To render a scene, you need to observe the actual environment, how the light reacts with different material, creating different highlight parameters and the planning of your scene, the shading, the light sources, the material used, the things to be emphasized is important before starting the rendering.
Some important techniques in Vray rendering engine to share here:-
1. Get Gamma correction right at 2.2/2.5 depending on the monitor you are working on and enable overriding of Gamma on material imported to avoid twice Gamma correction on materials to save time and better effect on light feature.
2 Lowering down the secondary bounces while rendering an internal scene and raise the contrast level in Irradiance Map in the GI column would create the same effect of adjusting the curvature of color level in Photoshop.
3. Test render with Light cache as primary and secondary bounces of light to save time when determining key light position would help saving time.
However, lighting a building or internal spaces is a profession and it would be very helpful to share your knowledge for users and readers. PLASA is one of international association for lighting and sound. to find out more...
Do leave comments for any techniques you intend to share.