Installation

In Blender open Edit, Preferences, Get Extensions, then use Install from Disk and pick the truck_generator zip.

Usage

1. Open the Truck tab in the 3D viewport sidebar (N). With nothing selected, click the picture to pick one of the 44 trucks, then press Add. You can also use Shift+A, Mesh, Truck.
2. The card at the top shows the truck. Click its picture to switch to another preset. Surprise Me makes a random truck, Variation changes the current one and New Seed reshuffles the load and small details.
3. Pick Tractor or Rigid, then click the Cab and Trailer pictures to change them. The Livery box sets the paint scheme and its colors.
4. Drive rolls the wheels, Steer turns the front wheels, Trailer Angle swings the trailer on the fifth wheel and Tip raises dump bodies. All four are animatable: Shift+click the buttons next to them to add a keyframe.
5. The closed sections below hold the details: cab, chassis and wheels, trailer and body, front and chrome, wear and export.
6. For game engines set Detail to Low and use Convert to Mesh; the meshes have UVs, the origin on the ground under the front axle and Principled BSDF materials.