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Image Based Lighting

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Any environment in MODO can be used to light a scene with the addition of 'Global Illumination', wether it is an image map, a gradient or even a solid color or procedural texture layer. Individually, layers dont have specific brightness or luminous settings, but their contribution to a scene can be adjusted by modifying the 'Opacity' value of the layer or globally with the 'Intensity' setting of the 'Environment Item' producing brighter, more evenly illuminated scenes or darker scenes, depending on how the settings are adjusted.

When global illumination is combined with High Dynamic Range (HDR) images, incredibly realistic simulations of real world light interaction can be produced, a technique known as image based lighting (IBL). HDR imagery is generated in such a way as to not only capture the colors of a scene but faithfully capture the brightness values as well, creating a dynamic range that far exceeds what most monitors are cabable of displaying. A full 360° panoramic HDR would capture any visible lights, exterior lighting (including the sun) and the skys contribution, and most importantly bounced light. MODO in turn is able to utilize this extended information and illuminate the scene. Because of HDRs abilty to capture such subtleties in a scene, scenes utilizing image based lighting are often indistiguishable from photographs producing a look that has become extremly popular, especially amongst visual effects artists, art directors wishing to absolutly control every aspect of an advertisers image and the CAD visulization crowd seeking to produce ever more realistic simulations for planning and marketing purposes.

A series of IBL renders utilizing the same settings, only the environment image has changed.
Robot A   Robot B   Robot C   Robot D
Robot model provided by John Hayes

Where Do HDRI's Come From?

HDR images used for IBL are often comprised of a series of photographs taken of the same scene. Each having a slightly different exposure (length of time the shutter is open). This sequence of images, ranging from extremely dark to extremely bright, are then combined in such a way that for every pixel, a color value and a brightness value can be calculated. (Photoshop has an automation command "Merge to HDR" that is capable of doing this; several free tools are availalbe that are capable of doing this as well. See external link HDR Labs for more info.)

HDR Dark
Sky exposure (-2 EV)


Default Exposure (0 EV)


HDR Bright
Forground Exposure (+2 EV)

The resulting HDR image can then be saved in a format that retains this information, such a EXR or HDR (16bit and lower formats will work but don't retain the brightness values necessary to properly illuminate the scene). When loaded into MODO, the brightness information is then extracted and used to illuminate the scene producing an incredibly realistic simulation of the lighting from the original scene.

Setting MODO for IBL

A few settings need to be in order first for image based lighting to work in MODO. But don't worry, it's all very easy to set up.

Tip icon

TIP: Don't happen to have any HDR images available? A great alternative that produces equally impressive results is the Physically Based Sky feature. This function can be enabled in the Environment Material item; use the 'Environment Type' dropdown to select. Please reference that page of the documentation for more information on setting it up.



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