Bridge

"""Simple example to calculate three stacked cubes"""

import os

import compas

import compas_cra
from compas_cra.algorithms import assembly_interfaces_numpy
from compas_cra.datastructures import CRA_Assembly
from compas_cra.equilibrium import cra_penalty_solve
from compas_cra.equilibrium import cra_solve
from compas_cra.equilibrium import density_setup
from compas_cra.viewers import cra_view

mu = 0.9
dispbnd = 1e-1
overlap = 0
d = 1

FILE_I = os.path.join(compas_cra.SAMPLE, "bridge.json")

assembly = compas.json_load(FILE_I)
assembly: CRA_Assembly = assembly.copy(cls=CRA_Assembly)
assembly.set_boundary_conditions([0, 1])

density = {node: 3.51 if node in [11, 12, 13, 14, 15] else 1 for node in assembly.graph.nodes()}
density_setup(assembly, density)

# assembly.delete_blocks([3, 4, 5, 6, 7, 8, 9, 10])
# assembly.delete_blocks([11, 12, 13, 14, 15])

assembly_interfaces_numpy(assembly, amin=1e-6, tmax=1e-4)

# the published screenshot was made with cra_solve; the penalty variant stays one
# uncomment away, as it was in 2022
cra_solve(assembly, verbose=True, density=d, d_bnd=dispbnd, eps=overlap, mu=mu)
# cra_penalty_solve(assembly, verbose=True, density=d, d_bnd=dispbnd, eps=overlap, mu=mu)
cra_view(
    assembly,
    resultant=True,
    nodal=False,
    grid=True,
    weights=True,
    # the published screenshot shows cone-headed resultant arrows (forcesdirect), even
    # though the 2022 file said forcesline - the image was made with uncommitted flags;
    # the image is the contract
    forcesdirect=True,
    forcesline=False,
    displacements=True,
    dispscale=1,
    scale=0.5 / d,
)