Rendering menu > Environment > Environment and Effects dialog > Environment panel > Exposure Control rollout > Choose Pseudo Color Exposure Control from the list. > Pseudo Color Exposure Control rollout
Pseudo Color Exposure Control is actually a lighting analysis tool that provides you with an intuitive way of visualizing and evaluating the lighting levels in your scenes. It maps luminance or illuminance values to pseudo colors that show the brightness of the values being converted. From darkest to brightest, the rendering shows blue, cyan, green, yellow, orange, and red. (Alternatively, you can choose a grayscale where the brightest values are white, and the darkest are black.) The rendering includes the colored or grayscale spectrum bar as a legend for the image.
Note: You can use the Pseudo Color exposure control with the mental ray renderer.
In the rendered frame window labeled “illuminance,” a legend appears below the image.
If you render a scene using this exposure control, a special render element named Illuminance is created in order to obtain accurate luminance and illuminance data.
Tip: If you get a file write error when you try to render a pseudo color image, check the path and file name of the Illuminance element, or the permissions of the PNG file that saves the illuminance data.
Quantity—Chooses the value being measured.
Style—Chooses the way to display values.
Scale—Chooses the technique used to map values.
Minimum (Min.)—Sets the lowest value to measure and represent in the rendering. Values at this quantity or below it all map to the leftmost display color (or grayscale level).
Maximum (Max.)—Sets the highest value to measure and represent in the rendering. Values at this quantity or above it all map to the rightmost display color (or grayscale value).
Physical Scale—Sets a physical scale for exposure control to use with lights that are not physically based. The result is an adjustment of the rendering that approximates the eye's response to the scene.
Each standard light's Multiplier is multiplied by the Physical Scale value to give a light intensity value in candelas. For example, with the default Physical Scale of 1500, a standard omni light is treated by the renderer and radiosity as a photometric isotropic light of 1500 candelas. Physical Scale is also factored into reflections, refractions, and self-illumination.
Tip: You need to set the Physical Scale when you use ray-tracing with self illumination. Set this value to the equivalent of the brightest light source in the scene. This will set the appropriate conversion scale for reflections, self-illumination, and all other non-physically based elements a material offers. In some cases, an object might reflect or emit more light than the brightest light object in the scene; in this case, use the object's Luminance value as the Physical Scale.
Range=0.0 to 200,000.0 candelas. Default=1500.0.
A single candle is approximately 1 candela (the unit can also be called a "candle"). A 100-Watt (W) incandescent light bulb is approximately 139 candelas (cd). A 60W bulb emitting in all directions is about 70 cd, while the same bulb with a reflector is about 4500 cd because the light flux is concentrated into a narrow angle.
Photometric lights are unaffected by the Physical Scale value.
General Guidelines for Physical Scale Values
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If you use only Photometric lights, IES Sun, and IES Sky, the Physical Scale value is disregarded, and you don't need to change it.
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If you use Standard lights, the Physical Scale value acts as a conversion scale that the radiosity engine uses to calculate energy. Set it to the equivalent of the brightest light source in the scene. This will set the appropriate conversion scale for reflections, self-illumination, and all other non-physically based elements a Autodesk VIZ material offers.
However, if you use the Affect Indirect Only flag in the Logarithmic Exposure Control, you don’t need to worry about the physical scale setting.
Spectrum bar—Shows the spectrum-to-intensity mapping. The numbers below the spectrum range from the Minimum to the Maximum settings.
When rendering with pseudo color, the spectrum bar is displayed beneath the pseudo color image, labeled either Luminance or Illuminance.