Normal Mapping Research Of Lightweight Mesh Model

Three-dimensional models have been applied in many fields as a new kind of media form,for instance,3D model is more and more used in simulation,3D game,3D animation and virtual reality technology.With the development of 3D model building software and the improvement of model reconstruction technology,the built 3D model has high precision,but it also causes a problem that the data of model and textures is huge.Under the situation of the application field of the three dimensional model expanding,the transmission and rendering of 3D models online consume a lot of time with limited capacity of graphics processing and network bandwidth.Therefore,decreasing the quantity of models' polygons,showing high fidelity models' rendering,increasing the speed of human-computer interaction and response have become an important topic in computer graphics.This paper puts forward an improved simplified algorithm of edge collapse based on butterfly pattern for the problem of slow rendering speed of 3D model on the Internet.The length of collapsed edge and the coplanar of its two triangles are fully considered in the cost calculation of collapsed edge,the collapsing sequence on the basis of collapse cost is more reasonable.When calculating the coordinate of a new collapsing vertex on the basis of the butterfly model,taking the influence of all triangles that including the two vertices of the collapsed edge into consideration.The calculated collapsing vertex can reduce the error of the simplified geometry.Aiming at the problem of how to improve the compression ratio under the premise of ensuring the quality,the improved method based on 3Dc algorithm is proposed.The minimum and maximum values of the whole normal mapping are figure out and interpolated.Then matching and recording the minimum and maximum number of each block of the normal mapping,and using the improved method of interpolation to fitting vertices of each component of a block.Finally,making the compression ratio further improved under the situation of keeping the normal information accuracy.In order to verify the effectiveness of the proposed algorithm,the above two algorithms are applied to the online display system of 3D artwork.The simplified compression of 3D model and the more realistic rendering are realized.After the model is simplified,the geometric error of the simplified model is reduced compared with the traditional simplified algorithm,and the low modulus of the normal map can be used to simulate the detail display effect of the high modulus.The experimental results show that the 3D model can not only ensure that the 3D model has a high sense of reality,but also greatly shorten the time consumed by the rendering and rendering of 3D models.