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LightWave 3D 8 Lighting Wordware game and graphics library phần 10

Khi có ánh sáng mặt trời trên bầu trời (hay ánh trăng cho rằng vấn đề), nhất sẵn có nguồn ánh sáng lấp đầy bầu trời. Trong thời gian ban ngày, điều này thường có nghĩa là một bầu trời màu xanh sáng. Trong đêm, nó thường có nghĩa là hầu như không cảm nhận được | Anatomy of a Production Lighting Rig Figure 27.6 The next issue to be dealt with was that the animal heads would move around and rotate during a shot. Naturally animals move their heads just like people do. The head moves were carefully matchmoved and we applied the finished motions to our geometry so that our CG heads would move in the same manner as the real animals heads. Note Matchmoving is a grueling brain-burning task involving taking geometrically imperfect geometry into Layout loading up the plate and making the geometry fit the animal on every single frame one frame at a time. If you ever meet a matchmover don t forget to give him cookies. It s a thankless job and has a rating of 11 on the tough-o-meter. Our problem lay in that our spotlights have cone angles. In other words there is a limited area where any given spotlight will illuminate something. Figure 27.7 If the head is moving around then either the cone has to be large enough to encompass the entire range of motion or the lights have to follow the head around as it moves. Both of these have their advantages and disadvantages. 467 Chapter 27 If we make the light cones all large enough that we never have to move the lights we never have to move the lights but we have a problem with shadow map resolution. We would have to crank up the shadow map resolution very high indeed so that the resolution was always high enough no matter where in the scene the object lay and this would have a serious impact on render times. Remember we re not talking about just one light calculating a shadow map we re talking about eight array lights a key light a fill light a rim light and a bounce light. That s 12 lights with 12 shadow maps. So if we have to ramp up our shadow map resolution from 1000 to 4000 to cover the area of movement that means it will take 16 times longer to calculate the shadow maps. We definitely needed a better solution than that In addition we wanted to keep the cone angle as narrow as possible so .