PBR-BookCh8ReflectionModelsReflectionModels(pbr-book.org)球坐标系中，使用\((\theta,phi)\)\(\theta\)givendirectiontothe\(z\)axis\(\phi\)theangleformedwiththe\(x\)axisafterprojectionofdirectionontothe\(xy\)lane.

关键词：泛化性、过拟合、欠拟合；误差、偏差、方差及其关系；模型复杂度&偏差&方差&过拟合&欠拟合&误差之间关系泛化性generalization:performancesonunseendatatrainingdata——seentestdata——unseen过拟合overfit:predictaccuratelyontrainingdata(smalltraining