Three-dimensional (3D) parameters are being increasingly used to characterise the pavement macrotexture. This study explores the influence of the evaluation area and sampling interval on the 3D macrotexture parameters. The point clouds of surfaces with different morphologies are captured by a 3D scanner, and is divided into non-overlapping rectangular areas with different sizes. The original point clouds are diluted to obtain data with different sampling intervals. The parameters concerned include the root-mean-square surface height Sq, the root-mean-square surface slope Sdq, the peak density Spd, the arithmetic mean principal curvature Spc, the volume of the peak material Vmp and the volume of the core material Vmc. The results indicate that parameters calculated within an evaluation area of 80*80 mm² can properly represent the macrotexture. The sampling interval influence parameters in the order Spc > Spd > Sdq > Sq, Vmp, Vmc. The conclusions lay the foundation for calculating 3D pavement parameters.

三维 (3D) 参数越来越多地用于表征路面宏观纹理。本研究探讨了评估区域和采样间隔对 3D 宏观纹理参数的影响。不同形态的表面点云被3D扫描仪捕获，并被划分为不同大小的不重叠矩形区域。原始点云被稀释以获得不同采样间隔的数据。相关参数包括均方根表面高度S q、均方根表面斜率S dq、峰密度S pd、算术平均主曲率S pc、峰材料体积Vmp 和芯材体积V mc。结果表明，在80*80 mm ²的评估区域内计算的参数可以正确地表示宏观纹理。采样间隔影响参数的顺序为S pc >  S pd >  S dq >  S q、V mp、V mc。结论为计算3D路面参数奠定了基础。