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  Lighting an underwater scene
   
 


STEP 1 - SET THE SCENE AND POSITION THE CAMERA
It is easiest to create your basic scene without the water, this allows you to position everything and do test renders in the shortest amount of time. Remember that the underside of the water will reflect whatever is below it so if you are creating a deep ocean picture you can delete the ground plane creating a feeling of infinite depth.

In this example I wanted to show a dolphin swimming in mid ocean. Therefore I imported my model, positioned the camera using the trackball options and then deleted the ground plane.



STEP 2 - ADD WATER
The next step is to add the water, to do this select the Infinite Water Plane. Adjust the position of the plane to create the desired effect. The water material used can affect the look and feel of scene, so experiment to find a suitable one, in this example I have used ‘Deep Blue’.






Even in the clearest water visibility is limited to 30 meters or so, to reproduce that effect you can use Bryce’s Sky and Fog controls.






Set the fog and haze colours to whatever colour required, in this case I have used a mid tone blue.

Fog acts like a thin layer of cloud and can be used to provide more depth, for this scene however haze is more important so fog was set to minimal values (3 – 0). Haze is what you see when a plane stretches to the horizon. With haze set to zero, the horizon will have a hard edge to it, so I set its value to near maximum (93).



STEP 3 - CAUSTIC LIGHTING
As sunlight enters the water, the uneven surface means that whatever is below is unevenly lit, to reproduce this effect, ‘caustic’ lighting is used. Create a spotlight (I tend to use the square spotlight as I find it easier to manipulate as I require) and in the Light Lab, set it to Infinite Light.

Select the Light Gel option, from the Pictures dialog select Load in the Bryce directory you can find a number of light gels, select Watery Reflection.tiff.












Position the light so that it mimics the angle of the sun, you may need to use more than one light (I used 3), so duplicate and reposition as required.



STEP 4 - UP LIGHTING
Tiny suspended particles in water reflect a small amount of light upwards, this is recreated by creating a round spotlight, reducing its height so that the beam covers a wider area and then rotating the spotlight 180 degrees to point upwards. The light should have soft edges and be fairly weak with cast shadow disabled, set the light colour as desired. Position the light under your figure.


STEP 5 - STREAMING LIGHT RAYS
In order to create the shafts of light playing through the water, two options are available; you can add them in post production or use Bryce’s volumetric lights. Using volumetric lighting is render time intensive and so should always be the final stage.






Firstly, create a spotlight, position it so that it is at the same angle as the caustic lights and the sun, the figure in your scene should be lit by this spotlight. Although not important in terms of lighting your figure the volumetric light will now have areas of shadow where the ‘sunlight’ is blocked.






In the Light Lab for the spotlight select Cast Shadows, Visible Object, Volume and Infinite Light. Set Edge Softness quite high and then use Intensity and Falloff to tweak the lights properties just right.

Perform your final render and you should have a realistically lit underwater scene.