The necessity of developing the envelop design software is discussed firstly in this paper. To develop the software, key technologies and problems are pointed out. After the software developed, we use it to solve several types of problems. By doing these, we come to the conclusion that the efficient envelop soft which waremeets our requirements in the function, and the result is correct.

Progressive collapse of building structure which may lead to great damage usually occurs under the extreme events. Considering the nonlinear dynamic simulation of building progressive collapse, the difficulties of computational mechanics were studied.Then the advantages and disadvantages of normal numerical methods to simulate the process of building progressive collapse were compared. Finally, the particle element method was introduced.

The method to get the information from IFC irregular model is studied in this paper.A simplified algorithm is presented in this paper using to express arc-beam.In order to validate the theory mentioned above, a sample application is studied at the end of the paper.The study results show that the theory presented in this paper can help to obtain modal information accurately from architectural model to structural model.

During the process of the structural analysis, the current amplitude, which only adjusts the beam moment while does not adjust the column internal forces, results in the unbalanced force in the beam-column joints, and does not consider the relation between the change of beam stiffness and the beam amplitude. This article explores one calculation method for the whole structure's amplitude, considering the stiffness change of the each beam. With the structure finite element analysis, the amplitude achieves the balance of beams, columns and joints internal force. Some representative examples of the results show that by reduction of beam end stiffness, the amplitude of frame could be done. When the reduction factor of beam end stiffness is equal to 0.4, the analysis result is consistent with the traditional amplitude coefficient of 0.85.