Basic Mesh Equilibrium

Summary

In this example, we construct a mesh from a meshgrid, fix the corner vertices, and compute equilibrium.

Code

from compas.colors import Color
from compas.datastructures import Mesh
from compas.geometry import Line
from compas.geometry import Point
from compas.geometry import Sphere
from compas.geometry import Vector
from compas_dr.numdata import InputData
from compas_dr.solvers import dr_numpy
from compas_viewer import Viewer

# =============================================================================
# Input
# =============================================================================

mesh = Mesh.from_meshgrid(dx=10, nx=10)

fixed = list(mesh.vertices_where(vertex_degree=2))
loads = [[0, 0, 0] for _ in range(mesh.number_of_vertices())]
qpre = [1.0] * mesh.number_of_edges()

for index, edge in enumerate(mesh.edges()):
    if mesh.is_edge_on_boundary(edge):
        qpre[index] = 10

indata = InputData.from_mesh(mesh, fixed, loads, qpre)

# =============================================================================
# Solve and Update
# =============================================================================

result = dr_numpy(indata=indata)

result.update_mesh(mesh)

# =============================================================================
# Visualize
# =============================================================================

forcecolor = Color.green().darkened(50)

viewer = Viewer()
viewer.renderer.camera.target = [5, 5, 0]
viewer.renderer.camera.position = [5, 4, 20]

viewer.scene.add(mesh, show_points=False)

for vertex in fixed:
    point = Point(*mesh.vertex_coordinates(vertex))
    residual = Vector(*result.residuals[vertex]) * 0.1

    ball = Sphere(radius=0.1, point=point).to_brep()
    line = Line(point, point - residual)

    viewer.scene.add(ball, surfacecolor=Color.red())
    viewer.scene.add(line, linecolor=forcecolor, lineswidth=3, show_points=False)

viewer.show()