A Level of Detail selection method for multi-type objects based on the span of level changed

Level of Detail (LOD) selection method is a key component in complex scene rendering and is widely used in time-critical systems. Many studies focus their efforts on developing the LOD selection method to deal with the problem which the scene contains small objects or objects with a single type. This paper gives a LOD selection method handling the situation that the scene contains multi-type objects while the data amount of these objects change dramatically. The preprocessing step of our work is using the extreme simplification way to simplify the objects with large number of primitives and using the Quadric Error Metrics to simplify the small ones. Then we calculate the span of level changed to each type of object separately. In runtime, we organize all the objects into a max heap by using the importance factor for rendering. We get the top element of the heap and change its level until the total data of objects satisfy the condition of time-critical method. Compared to existing solutions, our method is more suitable to the situation when the scene contains different type of objects.