3D Rigging for Games: How to Rig a 3D Model

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3D Rigging for Game Animation and Character Design

3D rigging is used for advanced skeletal animation in video games. It’s simple: the animator places bones inside the model, connects them with joints and explains how do they move. Motion designers and animators use it to animate game NPCs for gameplay and cutscenes. Also, rigging has benefits that hand-made animation hasn’t:

  • ease of adjustment — the animator can easily adjust movement of a 3D model, add new moves or transfer existing animations between characters;
  • quality of details — the animator can improve important animations to make the game look better. For example, he can “teach” the model to properly place feet on an uneven surface, so they won’t fall through the textures;
  • variety of visual features — with rigging game developers can achieve everything from simple ragdoll physics to complex connection between bones and 3D mesh to simulate real muscles.

If you need 3D rigging for your video game, you’ll need to hire an animator artist or outsourcing studio. We recommend you to go for outsourcing: usually it’s cheaper, and you will also get an experienced 3D animator artist and a manager to control the workflow.

3d rigging for games process

In Kreonit game art outsourcing studio we provide 3D rigging for body and facial animations. Read further to learn how 3D rigging is done.

What we need to start 3D rigging

It’s obvious, that for 3D animation we’ll need a 3D model. We use skeletal animation for human, animals, dragons and other living creatures with complex movement. Still, we can rig any 3D object like a spaceship or a treasure chest.

skeletal structure in rigging

If you still don’t have 3D models for your game, you may read our article about 3D modelling.

The next thing we need is the game design document. The animator needs to know about the game’s genre, gameplay mechanics and animation list, visual style, lore and backstory of the character he needs to rig. We need this because animation effects on how the players will react to the game. Imagine a Devil May Cry or Bloodborne monsters with funky cartoonish animation. In this case they won’t be fun to beat.

In sum:

  • genre — it defines where the camera is and helps the animator to made moves look cool and recognizable by player;
  • gameplay mechanics and animation list — basically, they tell what the animations will look like and used for. For example, if the main characters has two sword attacks — one with 2 damage and one with 5 damage — the more effective one must look “deadlier”;
  • visual style — of course, we can tell the visual style by looking at 3D model, but it’s better when you tell us the details;
  • lore and character’s story — a skilled thief must move with dexterity, while a knight in heavy armor may move clunky. Also, details about the game’s lore help us to adjust animation details to fit the story.

If you want to develop unique animations like advanced acrobatics, futuristic weapon reloading or a jello cat catching his tail we will need concept art and keyframes to fully understand what result you expect to get. If you don’t have that, we may make it under your guidance.

Preparing the model to 3D rigging

Not every raw 3D model can be rigged. 3D artists sometimes mess the mesh topology, make the original model in cool pose instead of T-pose or place the textures wrongly. From time to time our 3D modelers must repair those 3D characters to prepare them for the rigging.

The most important part of preparation is the T-pose — a pose, where the character stands with its arms outstretched. This pose is the easiest one to place the bones in correct areas, to assign mesh and to add solid elements which don’t bend while the character is moving.

A typical example of bad model preparation is Prince of Persia: The Two Thrones.

bad rigging example

Many gamers noticed how oddly Prince’s arms look — that’s because modelers failed with T-pose and proper meshing. Arms and torso look unnatural, chest muscles are made with textures instead of polygons and the Prince’s body feels like a bad rubber doll.

Where the rigging begins: adding the bones

3D rigging is based on bones. Just like the ray-tracing simulating actual light particles to make the lightning look real, skeletal animation in games simulates real skeleton movement to make the character move natural.

The first step of actual rigging is to create a skeleton inside the 3D model. It is simplified compared to real skeleton, because there is no need to use two bones for the forearm and twenty bones for the spine. Still, it depends on what the player will see and how detailed the animations must be. In third person games there is no need to replicate real palm bone structure if the player won’t see the palms closely or the character always has a sword in his hand. We’ll help you find that spots where you can use fewer bones and cut costs on 3D rigging outsourcing.

The next step is to assign the bone’s parental structure. This structure explains which bone will automatically move if its parent is moving. Parental structure helps to replicate the real muscles and tendons behaviors when it comes to bone engines and skinning. But at this time the animator simply tells: if this bone moves, that moves too. For example, if the shoulder joint moves, all bones of that arm change their position too.

3D rigging continues: adding motors and weight

Basically, our limbs move because we have joints. The muscles, which are connected with bones, are contracting and moving the body. We don’t need muscles in 3D rigging, because we can use joint motors.

Joint motors define how far the joints can bend. With help of parental structure they will simulate some natural muscle structures. For example, when the character turns his head, he will slightly turn the torso in the same direction. This will make animations look more natural.

But in general meaning the joint motors are the base of animation. The animators will teach the 3D model to move by assigning different functions to those motors. Every animation is just a code that says “Bend this joint for 32°, rotate this joint by 15° clockwise”.

After motors are placed, we need to weight the model.

3d rigging weighting

This is rather artistic process: the animator assigns mesh parts to particular bones. Now when this bone moves, the mesh moves too. Mesh located in intersection between two bones will be collapsing ad stretching along with animation to reduce “falling through” effect, when one part of a mesh gets inside the other.

Game 3D rigging outsourcing

3D rigging is a time-consuming process, because there are too many bones to add, joints to set and weight to assign. Unlike the 3D modelling or art creation, it is hard to distinguish bad and good rigging before the animation process start. One badly placed bone can turn a graceful elf into a crooked gorilla.

If you need your 3D models animation to be pleasant and fluid, you’ll need good animation team and rigging. It’s hard to find freelancers and control their work every day. It’s expensive to maintain own rigging & animation department. So the best way to animate the game character is to hire an outsourcing team.

Kreonit game outsourcing company has skilled animators and rigging artists ready to join your project. We’ll rig and animate everything, from cute guys like in Animal Crossing to strange creatures with many limbs like in Dark Souls.

Just fill the brief, explain your project, and we will tell you how we can help.

 

 

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