README.md

model3d

This is a collection of tools for programmatically creating, manipulating, and rendering 3D models.

The following image was created completely from models made with model3d, rendered with the render3d sub-package of model3d:

See the showcase example for details on how that image was created, and which models it uses (all of which are included in the examples directory).

Examples

If you are eager to get started, you may jump right into the examples directory. Most of these examples produce models which can be 3D printed, although a few are more focused on cool-looking renderings.

Here's a few examples you may want to check out first:

• vase - a 3D-printable vase. This example gives a really simple picture of how to create a custom model3d.Solid implementation and turn it into a mesh.
• heart_box - a 3D-printable heart-shaped box. This example incorporates a 2D image (a heart) into a 3D design using the model2d sub-package. It gives an overview of how to inset (i.e. shrink) shapes, and how to build 3D solids out of them.
• table - a multi-part 3D printable bedside table. This example shows how to compose simple solids into more complex solids. It also shows how to use the toolbox3d sub-package to print parts with built-in screws and screw-holes.
• cornell_box - a classic ray tracing demo. This example shows how to construct 3D scenes and objects and render them with the render3d sub-package.

Creating models as Solids

There are four ways to represent objects in model3d. These are Solid, Collider, Mesh, and SDF. The GoDoc has more information on these representations, so let's focus on the Solid.

A Solid represents an object as a boolean function, where the function returns true for points inside the object. In particular, a Solid is a simple interface:

type Solid interface {
	Min() Coord3D
	Max() Coord3D
	Contains(p Coord3D) bool
}

Due to their simple and flexible representation, Solids are easy to implement, compose, and derive from other shapes. The model3d package includes several APIs for composing solids, such as JoinedSolid and SubtractedSolid. It also includes several pre-built solids, such as Sphere, Cylinder, and Rect.

Once you have a Solid that you want to render or print, you can convert it into a triangle mesh using marching cubes. Here's an example of creating a sphere 3D model out of a Solid:

solid := &model3d.Sphere{Radius: 1.0}
mesh := model3d.MarchingCubesSearch(solid, 0.01, 8)
mesh.SaveGroupedSTL("output.stl")

The resulting .stl file output.stl can be loaded into external applications, sent to a 3D printer, etc.

Rendering models

The render3d sub-package provides a variety of ways to render a 3D model. For the easiest API, use render3d.SaveRandomGrid, which renders a model from a variety of random angles (but assuming the z-axis is the axis of gravity), and saves the renderings to a file. It can take *model3d.Mesh, model3d.Collider, and render3d.Object arguments, and automatically adds colors/textures if needed.

Here's an example when using this API to render a dog-bone-shaped box:

That rendering was created with this one line of code:

render3d.SaveRandomGrid("rendering_box.png", mesh, 3, 3, 300, nil)