Using Blockbench

Blockbench is a 3D modelling software designed for making low-poly and voxel models, making it suitable for making Minetest models. As Blockbench supports exporting to .obj it is very easy to create static models and export them directly into Minetest.

It is also possible to use Blockbench for making nodeboxes and animated models for Minetest, but this is more convoluted and requires additional programs to accomplish.

Static models

When opening Blockbench and creating a new model it will ask you about the model type. Pick generic model, which has no limitations and allows you to export to .obj for use with Minetest:

Once created, you are now in the editor which allows you to start modelling. Create some cubes, resize them and move them around, or create meshes where you can manipulate individual vertexes.

In terms of scale and the origin, the origin in Blockbench is the same as the origin in Minetest. So e.g. for a cube model mimicking a full node, the cube would have the position of (-8,-8,-8), size of (16,16,16) and centred around the origin:

The default scale in Blockbench when exporting to .obj is 16, which means that 16 Blockbench units equal 1 meter inside of Minetest. You can change this scale in Settings -> Export -> Model Export Scale.

Once you have a model, go to File -> Export -> Export OBJ Model to export it.

Once exported into your mod's models folder, it will also place a .mtl file along with any textures next to the exported model. The .mtl file is usually used to map a model's textures, but Minetest does not use this file and can be safely removed.

Minetest is able to load textures from the models folder, but if you want to keep all textures in the textures folder instead you can delete those too.

Since Minetest does not use .mtl files for loading model materials, you need to specify them in the code. For example, for a node with the mesh drawtype you specify the model textures in the tiles table:

minetest.register_node(":ozxa:red_block", {
    description = "Red block",
    tiles = { "ozxa_block_red.png" },
    drawtype = "mesh",
    mesh = "ozxa_block.obj"
})

Even if you have exported your model into an .obj file, make sure to save a .bbproject project file too! While Blockbench can import an existing .obj model, some amount of data gets lost during this process. It's best to save a project file and check it into Git such that you or someone else can come back to edit the model at a later date if necessary.

Nodeboxes

Minetest has a rather basic built-in model format for nodes consisting of a list of cubes called nodeboxes.

There is no direct nodebox export option in Blockbench, but as it allows you to add, move and scale cubes it is easy to use it to visualise a nodebox and manually convert it into nodebox coordinates.

You can also use the objtonodebox Python script which can take an .obj model and convert it into a nodebox definition. Simply export your nodebox to .obj from Blockbench and run it through the convert.py script.

Animated models

Currently Minetest only supports the .b3d and .x model formats for animated models. These are both very ancient model formats that Blockbench cannot export natively, so you will need to go via Blender to make animated models for Minetest.

Blockbench supports rigging models if you select the Animate tab in the top right corner. These animations are kept when exporting to GLTF which can be imported into Blender. Blender has a plugin available to export a model into .b3d which can then be used by Minetest. See Using Blender on the Minetest Wiki for more information.

In the future when Minetest has GLTF model support merged, it should be possible to export an animated model straight into Minetest from Blockbench.