There are three binary csg operations which can construct extremely complex objects from very simple primitives: union (\cup), intersection (\cap) and subtraction (i.e. difference).
This diagram shows the basic idea:
The code for this in our system would look this this:
using OpticSim # hide
cyl = Cylinder(0.7)
cyl_cross = cyl ∪ leaf(cyl, Geometry.rotationd(90, 0, 0)) ∪ leaf(cyl, Geometry.rotationd(0, 90, 0))
cube = Cuboid(1.0, 1.0, 1.0)
sph = Sphere(1.3)
rounded_cube = cube ∩ sph
result = rounded_cube - cyl_cross
Vis.draw(result, numdivisions=100)
Vis.save("assets/csg_ex.png"); nothing # hide
leaf
∪
∩
-
There are also some shortcut methods available to create common CSG objects more easily:
BoundedCylinder
Cuboid
HexagonalPrism
RectangularPrism
TriangularPrism
Spider
These are the types of the primary CSG elements, i.e. the nodes in the CSG tree.
OpticSim.CSGTree
OpticSim.CSGGenerator
OpticSim.ComplementNode
OpticSim.UnionNode
OpticSim.IntersectionNode
OpticSim.LeafNode
These are the internal types and functions used for geometric/CSG operations.
surfaceintersection(::CSGTree{T}, ::AbstractRay{T,N}) where {T<:Real,N}
inside(a::CSGTree{T}, x::T, y::T, z::T) where {T<:Real}
onsurface(a::CSGTree{T}, x::T, y::T, z::T) where {T<:Real}
Interval
EmptyInterval
DisjointUnion
OpticSim.isemptyinterval
OpticSim.ispositivehalfspace
OpticSim.israyorigininterval
OpticSim.halfspaceintersection
OpticSim.closestintersection
OpticSim.IntervalPool
OpticSim.IntervalPoint
RayOrigin
Infinity
Intersection
OpticSim.isinfinity
OpticSim.israyorigin