Also, the planeangles of these tools must always be identical to those of the thread forms.
同时，这些刀具的平面角必须始终与螺纹形状的平面角保持一致。
2
When bouncing your flash, at certain angles close to that perpendicular plane, direct light will hit your subject.
当使用跳灯时，即使闪光灯以接近垂直的角度向上方打光，但仍有扩散的光线直接照射到被摄体上。
3
Or add transparent graphics with computed transparencies perpendicular to the Earth plane to create a more realistic layered effect for all viewing angles.