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- """Animation of a block attached to a spring"""
- from vedo import *
- from vedo.applications import AnimationPlayer
- L = 0.1 # spring x position at rest
- x0 = 0.85 # initial x-coordinate of the block
- k = 20 # spring constant
- m = 20 # block mass
- b = 5 # viscosity friction (proportional to velocity)
- dt = 0.15 # time step
- v = vector(0, 0, 0.3) # initial conditions
- x = vector(x0, 0, 0)
- xr = vector(L, 0, 0)
- x0 = vector(-0.8, 0, 0)
- # Pre-compute the trajectory of the block and store it in a list.
- history_x = []
- for i in range(200):
- F = -k * (x - xr) - b * v # force and friction
- a = F / m # acceleration
- v = v + a * dt # velocity
- x = x + v * dt + 1/2 * a * dt**2 # position
- history_x.append(x)
- # Create the objects to be shown in the animation
- floor = Box(pos=(0, -0.1, 0), size=(2.0, 0.02, 0.5)).c('yellow2')
- wall = Box(pos=(-0.82, 0.15, 0), size=(0.04, 0.50, 0.3)).c('yellow2')
- block = Cube(pos=x, side=0.2).c("tomato")
- spring= Spring(x0, x, r1=0.05, thickness=0.005)
- text = Text2D(font="Calco", c='white', bg='k', alpha=1, pos='top-right')
- # Create the animation player and it's callback function
- def update_scene(i: int):
- # update block and spring position at frame i
- block.pos(history_x[i])
- spring = Spring(x0, history_x[i], r1=0.05, thickness=0.005)
- text.text(f"Frame number {i}\nx = {history_x[i][0]:.4f}")
- plt.remove("Spring").add(spring).render()
- plt = AnimationPlayer(update_scene, irange=[0,200], loop=True)
- plt += [floor, wall, block, spring, text, __doc__]
- plt.set_frame(0)
- plt.show()
- plt.close()
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