mask = opt.elements[(x-x0)**2+(y-y0)**2<=r1**2]
opt.add_passive_elements(mask)
# Fix points in center
bearing1 = opt.nodes[x0+r1+1,y0+1-1:y0+1+2,z0+1-1:z0+1+2]
bearing2 = opt.nodes[x0-r1+1,y0+1-1:y0+1+2,z0+1-1:z0+1+2]
opt.fix_nodes(bearing1, directions = ['x', 'y', 'z'])
opt.fix_nodes(bearing2, directions = ['x', 'y', 'z'])
de = 1
left = opt.nodes[x0-r0+de+1,y0+1,z0]
top = opt.nodes[x0+1,y0+r0-de+1,z0]
right = opt.nodes[x0+r0-de+1,y0+1,z0]
bottom = opt.nodes[x0+1,y0-r0+de+1,z0]
load_points = [left, right, top, bottom]
opt.load_nodes(load_points, 1, direction = 'x')
opt.add_load_case('y')
opt.load_nodes(load_points, 1, direction = 'y')
opt.add_load_case('z')
opt.load_nodes(load_points, 1, direction = 'z')
opt.run_optimization()
