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Tools

There are few useful tools that might help you explore.

Getting your hands dirty

Suppose you want to remove the front-facing faces of an object, in order to see inside. That's possible, but a bit of code is needed.

eyepoint(200, 200, 200)
axes3D(300)
setlinejoin("bevel")

include(dirname(pathof(Thebes)) * "/../data/moreobjects.jl")

objectfull = make(cuboctahedron, "the full object")
objectcut  = make(cuboctahedron, "the cut-open object")

map(o -> setscale!(o, 60, 60, 60), (objectfull, objectcut))

function cullfrontfaces!(m::Object, angle;
        eyepoint::Point3D=eyepoint())
    avgs = Float64[]
    for f in m.faces
        vs = m.vertices[f]
        s = 0.0
        for v in vs
            s += distance(v, eyepoint)
        end
        avg = s/length(unique(vs))

        θ = surfacenormal(vs)
        if anglebetweenvectors(θ, eyepoint) > angle
            push!(avgs, avg)
        end
    end
    neworder = reverse(sortperm(avgs))
    m.faces = m.faces[neworder]
    m.labels = m.labels[neworder]
    return m
end

function drawobject(object)
    pin(object, gfunction = (args...) -> begin
        vertices, faces, labels = args
        setopacity(0.8)
        sethue("grey80")
        if !isempty(faces)
            @layer begin
                for (n, p) in enumerate(faces)
                    poly(p, :fillpreserve, close=true)
                    @layer begin
                        sethue("grey20")
                        strokepath()
                    end
                end
            end
        end
    end)
end

sortfaces!.((objectcut, objectfull))
cullfrontfaces!(objectcut, π/3)

translate(-200, 0)
drawobject(objectcut)

translate(400, 0)
drawobject(objectfull)

@show length(objectcut.faces)
@show length(objectfull.faces)
length(objectcut.faces) = 10
length(objectfull.faces) = 14

The object on the left has had its four frontfacing faces removed. The one on the right is intact.

culling faces

Geometry

There are some basic geometry utility functions - some of them are analogous to their Luxor 2D counterparts.

General

Thebes.axes3D — Function
axes3D(n=100)

Draw labelled 3D axes at (0, 0, 0) with length n.

Thebes.carpet — Function
carpet(n; kind=:circular)

Draw a circular carpet centered at the origin, using current Luxor parameters.

If kind is not :circular, the carpet will be a square.

Points that can't be rendered are not included in the final shape.

Distances

Luxor.between — Function
between(p1::Point3D, p2::Point3D, x=0.5)
between((p1::Point3D, p2::Point3D), x=0.5)

Find a point on a line between two 3D points. If x is 0.5, the returned point should be halfway between them.

Luxor.distance — Function
distance(p1::Point3D, p2::Point3D)

Return the distance between two points.

Luxor.midpoint — Function
midpoint(pt1::Point3D, pt2::Point3D)

Find the midpoint between two points. See also between().

Rotations

Work in progress:

Thebes.rotateX — Function
rotateX(pt3D::Point3D, rad)

Return a new point resulting from rotating the point around the x axis by an angle in radians.

Rotations are anticlockwise when looking along axis from 0 to +axis.

Thebes.rotateY — Function
rotateY(pt3D::Point3D, rad)

Return a new point resulting from rotating the point around the y axis by an angle in radians.

Thebes.rotateZ — Function
rotateZ(pt3D::Point3D, rad)

Return a new point resulting from rotating the point around the z axis by an angle in radians.

Thebes.rotateby! — Function
rotateby!(m::Object, angleX, angleY, angleZ)

Rotate an object around the x, y, and/or z axis by angleX, angleY, angleZ.

rotateby!(m::Object, pt::Point3D, angleX, angleY, angleZ)

Rotate an object around a point by angleX, angleY, angleZ.

Thebes.rotateby — Function
rotateby(pt::Point3D, angleX, angleY, angleZ)

Return a new point resulting from rotating the specified point around the x, y, and z axes by angleX, angleY, angleZ.

rotateby(newpt::Point3D, existingpt::Point3D, angleX, angleY, angleZ)

Return a new point resulting from rotating the point by angleX, angleY, angleZ around another point.

rotateby(m::Object, angleX, angleY, angleZ)

Rotate a copy of the object by angleX, angleY, angleZ.

rotateby(m::Object, pt::Point3D, angleX, angleY, angleZ)

Rotate a copy of the object around a point by angleX, angleY, angleZ.

Position and scale

You can change the position and scale of things:

Thebes.setposition! — Function
setposition!(ptlist::Point3D, pt::Point3D)

Move points by a vector..

setposition!(m::Object, x, y, z)
setposition!(m::Object, pt::Point3D)

Set the position of object to Point3D(x, y, z).

Thebes.setposition — Function
setposition(m::Object, x, y, z)
setposition(m::Object, pt::Point3D)

Set the position of a copy of the object to Point3D(x, y, z).

Coordinates

Thebes.dotproduct3D — Function
dotproduct3D(a::Point3D, b::Point3D)

Finds the dot product of a and b