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重点难点易混易错点剖析复习重点:中心投影和平行投影、立体图形的展开与折叠、立体图形与其三视图的相互转化及识别.复习难点:立体图形与平面图形的相互转化是难点,掌握立体图形与相应平面图形的联系是突破的关键.易混易错点:观察几何体时要注意方向,否则容易画错、误判几何体.画三视图时,主视图、俯视图要长对正,主视图、左视图要高平齐,俯视图、左视图要宽相等,要把物体的边缘、棱、顶点都体现出来,看得见的部分的轮廓线画成实线,看不见的部分的轮廓线画成虚线.分清平行投影与中心投影的区别,判断平行投影与中心投影时,分别过每个物体的顶端
Difficulties and misunderstandings are easy to understand and the main points of error analysis: the center projection and parallel projection, the unfolding and folding of the three-dimensional graphics, the mutual transformation and identification between the three-dimensional graphics and the three views. Difficulties in the review: The mutual transformation of the three-dimensional graphics and the graphics is difficult Stereo graphics and the corresponding graphic contact is the key to breaking.Easy to mix and error points: When observing the geometry to pay attention to the direction, otherwise easy to draw wrong, misjudge the geometry.Three view, the main view, the top view to be long, the main View, the left view to high flush, top view, left view to be equal width, to the edge of the object, edges, vertices are reflected in the visible part of the outline drawn as a solid line, the invisible part of the outline of the painting Into a dotted line to distinguish between the parallel projection and the center of the projection of the projection to determine the parallel projection and center projection, respectively, over the top of each object