3D Models, Textures and Bone Animations for Games.

3D Models, Textures and Bone Animations for Games.

Overview: • Tools – Advantages & Disadvantages • Low-poly models – from scratch • Texturing – UV maps and skins • Bone Animation – setting up skeleton, inverse & forward Kinematics

The Tools • Blender • Maya * • 3DS • Wings 3D • Ultimate Unwrap * • Caligari Truespace * • Photoshop *

Blender • Pros: • Free, Relatively Powerful. • Can do skeletal animations. • Easy to import/export. • Cons: • Learning Curve; • counter-intuitive, “clunky” interface.

Maya • Pros: • Extremely powerful. • Well documented. • Elegant, fast interface. • Becoming industry standard. • Cons: • ~$2,000. • Very good, but not excellent UV mapping

3DS • Pros: • Very powerful. • Similar to Maya • Cons: • Expensive.

Wings 3D • Fast. • Easy to use. • Can make excellent Low-Poly models • Cons: • No animation / UV mapping. • Hard to make complicated / High-poly models

Ultimate Unwrap • Pros: • Best UV mapping tool on the market (in my opinion) • Very fast, simple interface. • View texture on model in 3D environment. • Automatically updates texture when saved • All the functionality of more expensive tools • Cheap (~$70) • Cons: • Only good for UV mapping • Not directly compatible with Maya • Need to “juggle” model formats *.obj -> *.mb

Caligari Truespace • Pros: • Relatively powerful • Decent skeletal animations • UV mapping • Cheap (couple hundred $ for latest version) • Cons: • Extraordinarily awkward interface • Somewhat slow

Photoshop • A necessity • Uses Layers • Highly Versatile tool set • Great for creating skins to texture models

3D Modeling Technique • Art through extrusion • Minimize Polygons

Art through Extrusion • Start with basic shape (cube) • Extrude a Face • Adjust size of face • Collapse vertices / edges to make angles • Repeat above • Use Symmetry

Minimize Them Polies! • Use triangular points (when possible) • Focus attention on salient areas • Rely on texturing for detail – keep it simple • Orient human models in standard position (shown)

Some Buildings… • Both < 20 polies

Some Space Ships…Both <80 polies

UV / Texture Mapping • Different Types • Methods • Minimize Size of Images

There’s more than one way to Skin a Cowboy… • Face Painting • Paint a fixed texture to individual faces • Pros: easy, fast • Cons: looks atrocious up close • Materials • Apply a “material” or surface texture to a face • Phong, Metallic, etc. • Diffuse, Ambient, Emissive, Specular, lightings • Pros: Looks really good. • Cons: Requires in-game light source. Expensive. • UV Mapping * • “Unwrap” polygon model to flat surface • “Paint a picture” over unwrapped polies • Pros: Can make low-poly models look good! • Cons: Difficult to learn / do well.

UV Mapping • Import Model • Unwrap as desired • Create Texture

Import Model • Disorganized UV map

Unwrap Model as Desired • Many Different Types • Box, cylindrical, plane, etc. • Make it “easy to paint” • Conserve space • Devote more space to salient parts

Paint Texture Onto Model • Use many layers (Photoshop / PSP) • Low opacity Air Brush for shading • Darken Edges & Brighten centers of polygons • Gives a more “rounded” appearance • Keep textures small!

Skeletal Animations (Maya) • Set up Skeleton • Organize bones into Hierarchy • Inverse / Forward Kinematics • Skinning Your Character • Get the MOST from your model

Set up Skeleton • Maya: Skeleton -> Joint Tool • Be anatomically accurate • Start from pivot; work outward • Use at least 2 perspectives

Use Mirror Joint • Orient Model to the Origin!!! • Only way to ensure symmetry • Much easier • Mirror Joint • Select highest-order bone: hip • Maya: skeleton -> mirror joint

Use Hypergraph • Label bones • Organize into hierarchy • Click / drag

Bind to Skin • Attaches skeleton to model • Maya: skin -> bind skin -> smooth bind+ • Set max influence = 1 • Too many slows down in-game animation

Time to Animate • Set a “neutral pose” • Select All • Key Everything at time = -10

Inverse Kinematics • Use IK Handles • Maya: Skeleton -> IK Handle Tool • Allows fast and positioning

OH NO! • Sometimes difficult to get specific pose… • Then use Forward Kinematics

Have animation reference • Easy to google • Search for image displaying desired animation keyframes

Loop Animations • Save Effort – Copy / Paste Keyframes • Click on keyframed object / IK handle • Right click on Maya Timeline -> copy • Move timeline -> paste

Create more animations • Skip a few frames • Select all • Key all • So animations don’t interpolate between each other • Skip a few more frames • Have at it!

Export your Animation • Can download exporter from Ogre3d site

3D Models, Textures and Bone Animations for Games.