To test it properly, I need a demo rorbot mod, ideally one made myself directly, in Blender, including the export and configuring. I have some Blender animation skills (~10 years rusty but still), so I decided to throw together a simple boxy figure. And while at it, I documented the steps to make it a tutorial.
This tutorial doesn't require any knowledge of Blender or Rigs of Rods - everything will be (gently!) explained. You need Blender 3.x - get it from https://www.blender.org/download/
Blender always starts up new project with a cube called "Cube". We'll make the character out of this cube, but we want to name it differently. In Blender, an "Object" is a container, an envelope of sorts, which holds one or more scene elements (meshes, lights, armatures, curves, whatever you need). Let's rename the Cube object.
Blender's "Gizmo" is the colored XYZ axis indicator in the top right corner of the 3D Viewport window. Click and drag with mouse to rotate camera. Click the letters to align camera view along that axis. Click -Z for "front orhographic" view.
Blender starts in Object mode, where you edit Objects. As I explained in previous steps, Objects are just envelopes, but they affect the contained mesh's position, rotation and scale. This means when you stretch the cube in Object mode, you will see the mesh stretched but in reality it will be the same shape, just deformed along with the Object. We want to actually edit the shape, so let's switch to Edit mode.
Click and drag the magnifier glass icon to zoom. Click the hand icon to pan. Note that the visual grid in the 3D Viewport is showing you scale in meters (and multiples/fractions of it when you zoom out/in). The starting cube is 2x2x2 meters in size.
By default, the objects in 3D Viewport are opaque, so you can't see (or select with mouse) the vertices on the other side. Let's enable X-Ray mode to make the objects transparent, both visually and for mouse selecting.
Step 9 - Deselect all verts, use Box select for bottom verts
The points which make up the cube are called vertices, or verts in short. Blender shows them bright orange when selected and black when unselected. To select all verts, press 'A' key. To deselect all verts, press 'Alt + A' keys. Finally, to activate Box select mode, press 'B' key. Then click and drag mouse to draw a box around the verts you want to select.
Mind the grammar please: there is one "vertex", but two or more "vertices"! So many people get this wrong like "1 vertice, 2 vertexes"... don't be like that!
Press 'G' to activate grab mode. Then move your mouse to position the selected verts. Use 'Enter' key or click left mouse button when done. Let's make this box a chest box of the figure. The green boxes are a mockup of the character we're going to create. Yes it will be just boxes floating in air next to each other, unconnected, for maximum simplicity.
Use 'Shift + D' to duplicate the selected vertices. This will put you to grab mode - move your mouse to position the new verts as character head. Then use scale mode to shrink it a bit.
Note that from now on, we have multiple separate cubes in the project, but they're nonetheless still a single mesh.
Now let's add hands by duplicating, moving and scaling the cube as we did before. However, we want to narrowen the hand cubes - not scale them down, just narrowen. To do that, activate Scale mode like before and then press 'X' on keyboard to constrain the scaling to just one axis. Blender will highlight the axis and add text in top left corner. Then scale like usual. You can press 'X' again to deactivate the constraint.
Move the camera using the gizmo. You'll see that everything but the head is too thick. To flatten it, we'll use scale mode like before, but we need the body verts selected. We could use Box select, but let's learn a new trick. Use 'A' to select all verts, then 'Shift + left mouse click' to unselect the head verts, one by one.
Blender's project files have .blend suffix. Blender has a backup feature - each time you save the project to an existing file, a .blend1, .blend2 etc... backup file is created from the previous file and it's backups.
Blender adds a new armature with 1 bone. We'll make this our torso bone. This will be an simplistic rig, just one central bone for the body, one for head, 2 for each hand and leg. Go to Edit mode with the Armature and select the bone by clicking it with mouse.
