Sunken Bas-relief Design Based On Normal Map

With the continuous development of the digital relief field,people are increasingly demanding the effect of digital relief,and the style requirements for digital relief are more diversified.This paper proposes innovative solutions to the two main problems of digital relief due to poor relief effect caused by discontinuity of depth value and single relief pattern.(1)The height field is constructed directly from the normal.The digital relief is related to the actual three-dimensional scene.When the illumination and the perspective meet the specific conditions,the effect of the digital relief and the three-dimensional scene will be very similar.When the perspective is fine-tuned,the plane will appear again.Unlike three-dimensional models,digital reliefs are more focused on the offset from the base plane,or on the offset of smooth surfaces.The traditional method is mainly based on the three-dimensional scene and regards it as the height field.Therefore,the traditional method has the problem of how to deal with the discontinuity in the depth value,and then refers to the correlation algorithm in the image processing to reduce the discontinuity of the height value,and keep the local details.The method based on the normal map is considered from two aspects.On the one hand,the detailed features of the model surface we need are actually represented by the change of the normal(curvature),and on the other hand,the height due to the front and rear occlusion.The field discontinuity can be improved in the normal field,constructing the height field from the normal field,and avoiding the influence of the object in space due to the difference between before and after.Although the normals will not be continuous,this is necessary for the various features to be represented in the relief.(2)Sunken bas-relief generation based on normal field.In view of the difference between the concave relief and the ordinary digital relief,the algorithm mainly solves the problem of how to make the relief surface or the outline to have a dent.For this problem,it is more reasonable to process from the normal angle than to process directly from the height field.Only the local normals need to be calculated to construct the sag features,and the final height field is obtained through the integral calculation.Therefore,it is not necessary to directly process the height values.The discontinuity problem.The main steps are to extract the contour line and the important internal inline features from the normal map,calculate the distance map and its normal map;adjust the normal information of the basic plane;then combine the outline and basic normal line into a whole normal map;the height field is finally reconstructed from the composite normal map.