celer / csg

Constructive Solid Geometry (CSG) and Quick Hull Library for golang

Introduction

This is a Constructive Solid Geometry and Quick Hull implemention in golang.

The CSG implementation is based upon https://github.com/jscad/csg.js/

The QuickHull implementation is based upon https://www.cs.ubc.ca/~lloyd/java/quickhull3d.html

You should also investigate SDFs as a better alternative to traditional CSG methods, see https://github.com/deadsy/sdfx

Basic usage

CSG

s1 := NewCube(&CubeOptions{Size: &Vector{2, 2, 2}})
s2 := NewSphere(&SphereOptions{Center: &Vector{1, 1, 1}, Radius: 1.2, Slices: 15, Stacks: 15})
    
c:=s1.Subtract(s2)

out, err := os.Create("v.stl")
if err != nil {
    panic(err)
}
c.MarshalToASCIISTL(out)
out.Close()

will result in:

Hulling shapes:

h := &Hull{}

s1 := csg.NewSphere(&csg.SphereOptions{Center: &csg.Vector{0, 0, 0}})
s2 := csg.NewSphere(&csg.SphereOptions{Center: &csg.Vector{4, 0, -4}})
s3 := csg.NewSphere(&csg.SphereOptions{Center: &csg.Vector{4, 0, 4}})

err := h.BuildFromCSG([]*csg.CSG{s1, s2, s3})
if err != nil {
	panic(err)
}

c := h.ToCSG()
out, err := os.Create("v.stl")
if err != nil {
	panic(err)
}
c.MarshalToASCIISTL(out)
out.Close()

will result in:

Why?

I do a lot of OpenSCAD programming and I was hoping to find a way to build a more preformant and automatable tool-chain for 3D programming, plus I wanted to get my 3D math and understanding to a better place. Anyways while building this library I discovered SDFs (Signed Distance Functions), which is where I'll re-focus my efforts because it they seem like ultimately a more flexible approach to CSG rather then a mesh or polygon approach, I recommend seeing https://github.com/deadsy/sdfx as it's where I'm going to refocus my efforts.

csg's Issues

Incorrect output

Hi, This looks very interesting, but it doesn't seem to work. The output is jumble of triangles. Could you confirm the code in the repo is correct. Thanks.