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Studio Photography Techniques in Rendering: Gobos and Reflectors

This post has been on the back burner – my desktop – for a while, so it is with great pride I hit publish on this bad boy. The trick to overcoming procrastination: pretend someone’s telling you to slack off and suddenly work becomes that much more appealing! Anyway, on to the post. When doing 3D, in any renderer, I use very traditional studio photography techniques to create appealing lighting and most of this centres around reflector cards (things that bounce light) and gobos (things that block light). 3D renderings are often dull due to uncreative lighting, not poor modelling and novice to intermediate level 3D artists struggle with this the most since it involves thinking like a photographer.

The basic reasoning behind using a reflector card is that it gives more interesting reflections and bounces light back on objects without creating additional lights, which some people like to use but I find unneeded and just adds to render times. I’ve art directed a lot of product photo shoots and 60% of the time at a shoot is just watching the photographer move white cards and gobos to create the most interesting reflections and refractions. Some examples:


Getting that balance of stark light falloff and subtle gradations is done with a masterful handling of reflectors and gobos. In my still renders, these are key to making the objects look interesting and appealing. This can scene is a pretty simple anisotropic reflection with lots of controlled reflections and lights:

The lighting and reflectors (click for high res):

Even for scenes that don’t need that kind of dramatic product delineation, mixed-colour reflectors create the illusion of environment and add needed variation to surfaces. The renders below shows the roof without any reflectors and the bottom with some hidden reflectors:

That’s using the same lighting – only the reflectors have changed. It’s a huge difference and it’s very easy to do. Make a plane with a diffuse Ward Lambert material (almost pure white, black or coloured) place it so that light is bouncing how you want it relative to the camera (incident rays) and turn off primary visibility and Casts/Receives Shadows in the Render flags of the shape node for the plane:

That way, the reflectors don’t create shadows and they don’t appear in the renders. They will still affects ambient occlusion (V-Ray Dirt ExtraTex passes) though, so you’ll need to turn that off for AO passes with exclusion sets. After that, you’re good. Experiment with coloured reflectors – often these will add interesting elements to your reflections, like the red touches on the conveyor belt with the woman’s shoe here:

That’s a concept/shoot/rendering that I art directed and planned for enRoute magazine. The photography is by Jaime Leblanc.

If you’re interested in learning more studio photography techniques that will help improve your lighting and rendering, the book Light: Science & Magic is excellent.

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