In this tutorial, you will learn how to rig and animate a Semi-Trailer Truck in 8 minutes using Blender 2.83.
What you will need
- Blender version 2.8 or higher
- The truck/puller and Trailer models separated into two different collections/layers. The wheels should be separate from the body.
- Blender Rigacar addon. Available at GitHub in the following link https://github.com/digicreatures/rigacar/releases/download/v6.0/rigacar.v6.0.zip (Thanks to David Gayerie of digicreatures.net for this amazing addon)
The rigging process
- Install Blender Rigacar addon after downloading from the link above
- Ensure your truck and trailer model is facing –Y (negative Y) direction in the blender viewport. The wheels should touch the top of the grid, like standing on it.
- Apply ‘Location’, ‘Rotation’, and ‘Scale’ transformations.
- Select every object in the scene and set the origin to geometry.
- Rename the wheels and body control objects as follows to let the add-on discover the structure of your models (See image below): Semi-Trailer trailer naming guide for rigging in blender
Rigging the truck/puller
- Hide the trailer by clicking on the trailer collection eye icon in the layout panel.
- Select all objects of your Truck model by clicking ‘A’ on your keyboard. Then click ‘Shift+A’. In the drop-down go to ‘Armature’ then select ‘Car (deformation rig)’. Rig a car addon will automatically generate an armature and parent the wheels and body to their respective control bones.
- In object mode, select the new armature. Click ‘N’ on your keyboard to reveal the properties panel and go down to the ‘Rigacar’ tab.
- Click on ‘Generate’. Your truck is rigged now.
- Add an empty and place it under the truck as displayed. Rename it to ‘Couplin’ (see image below)
Parent the ‘Couplin’ to the ‘TRUCK-Body’
Rigging the trailer
- Hide the truck by clicking on the truck collection eye icon in the layout panel.
- Repeat the same process from step 2 to 3 under ‘Rigging the truck/puller’
Animating your truck and trailer
We are going to start with the trailer then the truck. It is easier that way.
Animating your trailer
- Add a curve path and model the path you want your trailer to pass.
- In pose mode, select the ‘Root’ bone of your trailer and go to bone constraints. Add a ‘Follow Path’ constraint. On ‘Target’ section, select ‘NurbsPath’.
- Still on the Follow Path constraint tab, tick ‘Follow Curve’ and ‘Fixed Position’ options. On ‘Forward’, select –Y (negative Y). Now when you move the ‘Offset’ value between 0 and 1, the trailer moves along the ‘NurbsPath’.
- Add a plane that you will be using as ground or road. Place it on the same position as the grid.
- Make the plane slightly uneven using the displacement modifier. Then apply Location transformation by clicking ‘Ctrl then A’ then selecting ‘Location’.
- Select the trailer armature and go to pose mode.
- Click ‘N’ to reveal the properties panel
- On the ‘Rigacar’ tab, select one picker at a time to select your plane/road as shown in the video above.
- In pose mode when you select the ‘Root’ bone of your trailer and move the ‘Offset’ value of the ‘Follow Path’, constraint, it moves and reacts to the uneven road.
- On the ‘Rigacar’ tab, change ‘Wheels on Y-axis’ value from 0 to 1. Click on ‘Bake wheels rotation’.
Animating the truck
- In pose mode, select the ‘Root’ bone of the truck. Repeat the same process from step 3 to 4 under ‘Animating your trailer’
- Move the ‘Offset’ value of your truck until it is right in front of your trailer as a normal trailer. Note the difference between trailer and truck ‘Offset’ values somewhere on paper.
- On frame 1, insert keyframes on the trailer and truck ‘Offset, values by clicking the letter ‘I’ on the keyboard.
- Go to the last frame in the timeline and move your truck’s ‘Offset’ value to 1. Insert another keyframe.
- Still, on the last frame, move your trailer’s ‘Offset’ value to 1 minus the difference you noted on paper. Insert another keyframe of the new ‘Offset’ value.
- Repeat the same process on your truck as step 9 under ‘Animating your trailer’. Then click on ‘Bake car steering’. Play your animation and the truck and trailer will move along the path.
- In pose mode, add a ‘Damped Track’ constraint to the ‘Root’ bone of your trailer. Under ‘Target’ select the ‘Couplin’. ‘To’ select –Y (negative Y). Now your trailer appears hooked to the truck when in motion.
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