Boundary smoothing for volume rendering of 3D lithology grid model in engineering geology
ZHOU Ying
NIU Lujia
WANG Zhangang
ZHANG Xi
XU Zhaoshang
Abstract：Objectives In order to solve the sawtooth problem caused by the discontinuous transition of litho-logic attribute at the boundary of rock strata in the volume rendering process of 3D lithology grid model in engineering geology,Methods a boundary linear smoothing method of 3D lithology grid model subdivision is proposed.According to the characteristics of horizontal continuity of rock strata and the rationality of spa-tial superposition relationship in vertical direction,and drawing on the idea of connecting adjacent borehole rock formations to the geological interfaces,the lithologic grid is organized into a form of regular division in horizontal direction and vertical recording of top and bottom elevation values of rock segments.Similar to a regularly distributed virtual hole(called a vertical column pillar).Based on this kind of organization form,in the process of light projection,four strata formation around the sampling point are used to form attribute cal-culation units,and define the strata connection rules and 16 subdivision templates.Linear calculation of lithological properties at any point in the model space is realized.Results Through the implementation and verification of WebGL2.0 in GPU,it is concluded that the rock vertical boundary on the longitudinal direc-tion can be significantly smoothed,which solves the sawtooth problem in volume drawing of rock boundaries.Finally,the calculation of the lithologic attribute at the sampling point is realized and the effect after smoothing is obtained.Conclusions The results show that the characteristics of the rock strata are combined with the spatial sampling process of the volume drawing ray projection algorithm,and the smoothing effect is good for the engineering geological rock strata with the assumption of horizontal continuity,and provide a new idea for the visualization of lithology grid in engineering geology.However,because there is no clear se-quence relationship between rock strata,the belt fault model cannot be processed,nor can the transverse dis-connection of large dip rock strata be dealt with.
Keywords：3D lithology gridray castingaliasing problemvolume renderingsmooth
Publication Date：2024-04-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 77-87 )