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further vnf_volume speed improvement

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Adrian Mariano 2020-06-13 21:56:15 -04:00
parent 224555a9ec
commit 57034ac955
1 changed files with 3 additions and 7 deletions
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vnf.scad
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@ -357,17 +357,13 @@ module vnf_polyhedron(vnf, convexity=2) {
// Returns the volume enclosed by the given manifold VNF. The VNF must describe a valid polyhedron with consistent face direction and // Returns the volume enclosed by the given manifold VNF. The VNF must describe a valid polyhedron with consistent face direction and
// no holes; otherwise the results are undefined. Returns a positive volume if face direction is clockwise and a negative volume // no holes; otherwise the results are undefined. Returns a positive volume if face direction is clockwise and a negative volume
// if face direction is counter-clockwise. // if face direction is counter-clockwise.
// Algorithm adapted/simplified from: https://wwwf.imperial.ac.uk/~rn/centroid.pdf
function vnf_volume(vnf) = function vnf_volume(vnf) =
let(verts = vnf[0]) let(verts = vnf[0])
sum([ sum([
for(face=vnf[1], j=[1:1:len(face)-2]) for(face=vnf[1], j=[1:1:len(face)-2])
let( cross(verts[face[j+1]], verts[face[j]]) * verts[face[0]]
v0 = verts[face[0]],
v1 = verts[face[j]],
v2 = verts[face[j+1]],
n = cross(v2-v0,v1-v0)
)
v0 * n
])/6; ])/6;