In engineering drawing, it is always inconvenient for orthographic projection to solve some measurement and orientation problems.
由于在工程图学中，用正投影法解决画法几何中的某些度量和定位问题往往很不方便。
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In this paper, we acguired a way of seeking shade and shadow of spheric surface in orthographic axonometric projection drawing by means of changing axonometric projection.