Robert Edmond Jones once remarked that the art of lighting was quite simple: merely put the light where you want it, and take it away from where you don't want it. What he didn't say was that the craft of lighting is quite difficult, especially during the past four decades as the call for more sophisticated lighting effects has become more demanding and the instruments needed to facilitate these changes more varied and complicated. As a result, a new profession was born, the lighting designer, and those who, like Jones, once took responsibility for lighting their own sets have now all but relegated that task to others.
Scenographers who design their settings within computer three-dimensional environments, however, must once again consider how those settings are seen under the effects of stage lighting, at least for the time they still reside within the computer's memory.
Many lighting designers have, of course, adopted computer object-oriented drawing programs (CAD) into their practice. Using the computer, they are able to make plans and elevations that accurately predict the position and focus of instruments, as well as the sequence and timing of cues.
For scenographers constructing three-dimensional models, however, the ability to light those models does not match the accuracy of outcome that lighting designers enjoy. For scenographers, the results obtainable (at least for now) only roughly approximate how settings appear in actual real-world theaters.
Nonetheless, the careful attention paid to lighting three-dimensional models has its rewards. Chief among these is the ability of the modeler to create renderings that emulate what eventually will be seen on the stage. If nothing else, these renderings provide a good starting point for discussions between scenographers and lighting designers or between others who need to know how settings appear under performance conditions. Approximate as this information is, it has its uses.
In both Strata Vision 3d and Strata Studio Pro, three basic light resources are available that operate almost identically to the ways that lighting instruments behave in real-world theaters. These are:
Directional Lights: These lights are also called Global lights. As with the sun, they provide a general ambient coverage and have a specific direction to the light source. These lights can be placed anywhere within the model space (similar to the way that the sun can have different positions according to the time of day it is seen). Unlike the sun, there can be more than one Directional light. These lights can be dimmed or brightened and can have their light color changed.
Spot Lights: These lights emulate lighting instruments in the theater in that they are directional, can be placed in any position, be angled to any point, have their focal widths changed, can have their beams either hard-edged or soft-edged, and can be dimmed or brightened to precise percentage levels.
Point Lights: These lights are multi-directional; that is, they shine equidistantly in all directions at once. The closer they are to a model object surface, however, the brighter that surface becomes. They can be placed anywhere within the model, have color mediums attached, and be dimmed or brightened to precise percentage levels.
In addition to color mediums, all lighting resources can have opaque patterns (called gobbos in real-world lighting practice but called Gels in the Strata Programs) to throw patterns of light and dark on model surfaces.
Lighting instruments in both Strata programs are set in dialog boxes like that shown below in Figure 1. Spot lights have the option to cast shadows or not and to have soft or hard edges to the projected beams.
Fig. 1 Dialog Box for Setting Strata Vision 3d and Studio Pro Spotlights
Figure 2 shows an isometric view of a model with general light provided by the Directional (or Global light), one front Spot light with soft focus, one back Spot light with hard focus and two multi-directional Point lights.
Fig. 2 Isometric View of Lighting Positions for Aida
Both Strata programs are able to capture front and side elevations, as well as top and isometric views. Often these views show more clearly the effect of the light than do normal perspective views (see Figure 5 below).
Figure 3 is a side elevation that shows the vertical height and angles of the Spot lights (S) and the vertical heights of the Point lights (P). Here a Directional light (A) or Global light is placed at the front left side of the proscenium arch.
Fig. 3 Side Elevation View of Lighting Positions for Aida
Figure 4 is a front elevation that shows very clearly the effect of the lights used in this model on the three-dimensional forms.
Fig. 4 Front Elevation View of Lighted Setting for Aida
Figure 5 is a perspective view of the setting as seen from the middle of the auditorium.
Fig. 5 Perspective View of Lighted Setting for Aida
Principles For Computer-Generated Models
Here are a few principles that should be followed in lighting a computer-generated three-dimensional model. They are not meant as general guidelines for the construction of actual CAD-based lighting plots. (Although many lighting designers now practicing should take some heed of the first general principle listed below, since many productions are woefully over-lighted simply because the instruments exist and the capacity for power available.)
Keep the model light plot simple.
Select one moment from the scene and light that moment.
Use one Directional light for general illumination and tonality (Fig. 6).
Use only one or two Spot lights for emphasizing focal points (Fig. 6).
Use only one back Spot light so that shadows from one direction does not wash out shadows from another.
Use Point lights for soft light near where a spot light has been focused. This not only helps blend the spotlighted area but also gives controllable coloration to the specific area.
Use Point lights to bring general light the the back parts of the setting (Fig. 7). Point lights are also useful in illuminating background images.
Use the Soft edges option to blend lighting sources together (Fig. 8).
Fig. 6 Aida Act II - Sc. 2 High Ambient Light - No Back Light
Fig. 7 Aida Act II - Sc. 2 High Ambient Light - Point Lights Added to Rear
Fig. 8 Aida Act II - Sc. 2 Low Ambient Light - Soft -Edge Spot lights
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