利用这一规律和作图方法，可以解决任意位置的非退变二阶曲面的投影轮廓线的作图问题。

By using the role and the drafting methods, projective contour line of a quadric at random position can be drawn.

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分析了圆锥轴线为正平线时，在水平面投影图中轮廓线的投影。

The H-project of a cone whose axis is parallel to V-plane is analysed.

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分析了圆锥轴线为正平线时，在水平面投影图中轮廓线的投影。

The H-project of a cone whose axis is parallel to V-plane is analysed.

youdao