立体图形截面演示

GeoGebra 命令及参数

1. Pyramid((2, 2, 0), (-2, 2, 0), (-2, -2, 0), (2, -2, 0), (0, 0, 5)) → a, face5, edge3, edge5, edge7, edge8, face1, face3, face4, face2, edge1, edge4, edge6, edge2
2. IntersectPath(b, a) → poly1, A, B, C, D, f, g, h, i
3. Midpoint(A, D) → E
4. Midpoint(B, C) → F
5. Rotate(b, (-α), Segment[E, F]) → b'
6. Rotate(b', β, zAxis) → b''
7. IntersectPath(b'', a) → poly2, G, s, H, I, J, K, j, k, l, m
8. Segment((0, 0, zz), (0, 0, 5)) → n
9. Rotate(n, α) → n'
10. Rotate(Rotate[n, (-α), Segment[E, F]], β, zAxis) → p
11. Rotate(Rotate[(0, 0, 5), (-α), Segment[E, F]], β, zAxis) → L
12. Rotate(Line[E, F], β) → q
13. Rotate(Rotate[{J, K, G, H, I}, α, q] - (0, 0, zz), (-β), zAxis) → list1
14. Polygon(list1) → poly3
15. RemoveUndefined(list1) → list3
16. Sequence(Segment[Element[list3, Mod[i, Length[list3]] + 1], Element[list3, Mod[i + 1, Length[list3]] + 1]], i, 1, Length[list3]) → list2
17. Polygon(list3) → poly4