$\Large 矩形$

演示

制作教程：

α = 0 rad (slider from 0 to 6.283185307179586, step 0.01°)
a = Surface(cos(θ), sin(θ), h, θ, 0, α, h, 0, 3)
q1, f, g, h, i = Polygon((0, 0, 0), (1, 0, 0), (1, 0, 3), (0, 0, 3))
q1' = Rotate(q1, α, zAxis)
q2, j, k, l, m = Polygon((0, 0, 0), (2, 0, 0), (1, 0, 3), (0, 0, 3))
q2' = Rotate(q2, α, zAxis)
b = Surface(((3 - h) / 3 * cos(θ)), ((3 - h) / 3 * sin(θ)), h, θ, 0, α, h, 0, 3)
d = Surface(((1.5 * sin(u)) * cos(v)), ((1.5 * sin(u)) * sin(v)), (1.5 * cos(u)) + 1.5, u, 0, π, v, 0, α)
c = Surface(((6 - h) / 3 * cos(θ)), ((6 - h) / 3 * sin(θ)), h, θ, 0, α, h, 0, 3)
n = 1 (slider from 1 to 4, step 1)
t1, p, q, r = Polygon((0, 0, 0), (1, 0, 0), (0, 0, 3))
t1' = Rotate(t1, α, zAxis)
s = Line((0, 0, 0), (0, 0, 1))
e = Semicircle((0, 0, 0), (0, 0, 3), yAxis)
e' = Rotate(e, α, zAxis)
A = (0.312, -5.252)
B = (3.772, -5.252)
C = (-2.748, -4.752)
D = (0.352, -4.752)

Tool: 简易坐标系
请选择原点，分别输入：x最小、最大值，y最小、最大值
Input: A, a, b, c, d
Output: B, C, O, u, v

$\huge\textcolor{}{x}$

$\huge\textcolor{}{y}$

$\Large\textcolor{}{O}$

A: (0, 0)
u = Vector(A + (a - 1, 0), A + (b + 1, 0))
v = Vector(A + (0, c - 1), A + (0, d + 1))
B: A + (b + 1, 0)
C: A + (0, d + 1)
O: A