The method is based on the observation that many objects have texture repeatedly laid on different locations of their surface.These samples form a pretty sparse set of BTFs.

• 这个方法是藉由观察现实生活中的物体都含有某种纹理重复的出现在物体的表面，而这些重复出现的纹理可以形成一个较为稀疏的纹理函数模型。