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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 *
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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
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