Shape

Shape generation and utilities

generate_convex_mesh

 generate_convex_mesh (n_points:int=10, n_refinement_steps:int=3)

Generate a 2D convex mesh

	Type	Default	Details
n_points	int	10	number of points in the convex shape
n_refinement_steps	int	3	number of refinement steps
Returns	tuple		mesh and points in the normalized range [-1.0, 1.0]

source

generate_convex_shape

 generate_convex_shape (n:int)

This function was taken and adapted from https://stackoverflow.com/a/68602707

Generate convex shappes according to Pavel Valtr’s 1995 alogrithm. Ported from Sander Verdonschot’s Java version, found here: https://cglab.ca/~sander/misc/ConvexGeneration/ValtrAlgorithm.java

returns a numpy array of shape (n, 2)

def rasterize(
    side: int,  # side of the image
    points: np.ndarray,  # points defining the shape
) -> np.ndarray:  # rasterized shape as a boolean array
    """
    Rasterize a shape defined by a set of points
    """
    return polygon2mask((side, side), ((points + 1.0) / 2.0) * side).T

Generate random convex polygons and rasterize them.

mesh, points = generate_convex_mesh(10, 3)

system = System(MATERIALS['polycarbonate'], mesh)
eigenvalues = system.eigenvalues
eigenvectors = system.get_mode_gains()


fig, ax = plt.subplots(1, 2, figsize=(10, 5))


MeshTri.draw(mesh, shading={"wireframe": True}, ax=ax[0])
ax[0].set_xlim(-1, 1)
ax[0].set_ylim(-1, 1)
ax[0].set_title("Mesh")
ax[0].set_xlabel("normalized x")
ax[0].set_ylabel("normalized y")

mask = rasterize(128, points)
ax[1].imshow(mask, origin="lower")
ax[1].set_title("Rasterized shape")
ax[1].set_xlabel("pixels x")
ax[1].set_ylabel("pixels y")

Text(0, 0.5, 'pixels y')