Abstract: Cloud platform becomes a necessity to store and manage huge data for complex applications.The task of Building Information Modeling (BIM) is to organize the relevant data and work collaboratively during the whole life-cycle of the construction informationize.BIM is in urgent need of cloud computing.How to build a supercomputing model on cloud platform is a big challenge when facing the complex BIM application.This paper presented a framework of cloud services for BIM application.Hadoop is a distributed software framework.The four layers of the framework were designed:cloud storage,cloud platform services,application services and client applications.The retrieval algorithm of urban spatial location was proposed on the framework,which uses the improved KD tree as index table.The paper presented the load balancing algorithm for spatial location retrieval by which many groups of users access the data block concurrently.By statistical access frequency of the nodes,the strategy of balanced distribution for data block was designed.Experiments show that the framework has the characteristics of concurrent processing capability and rapid response for building information.

Key words: Cloud computing,Building information modeling,Framework,KD tree,Spatial location retrieval,Load balancing