2. To create a rectangle or oval with 3D effects, select the desired shape from the basic shapes menu. 要创建一个具有3D效果的矩形或椭圆形,从基本形状菜单选择所需的形状。
3. This subject introduce some common rectangle ore pillars and its advantages, and rock mechanics analysis and evaluation of rectangle ore pillars support effects. 介绍了几种常见矩形矿柱及其优点,并对矩形矿柱的支撑效果进行岩石力学分析和评价。