COMPUTER GRAPHICS CS 482 – FALL 2015 NOVEMBER 5, 2015 ANIMATION ANIMATION PROCESSES INTERPOLATION-BASED ANIMATION HARDWARE ISSUES KINEMATICS DYNAMICS

ANIMATION PROCESSES CS 482 – FALL 2015 MOTION PERCEPTION NOVEMBER 5, 2015: ANIMATIONPAGE 226

ANIMATION PROCESSES CS 482 – FALL 2015 TRADITIONAL ANIMATION PROCESS NOVEMBER 5, 2015: ANIMATIONPAGE STORYBOARDS2.DIALOGUE3.SKETCHING 4.IN- BETWEENING 5.INKING 6.PAINTING 7.BACKGROUND S 8.PHOTOGRAPHIN G 9.EDITING

ANIMATION PROCESSES CS 482 – FALL 2015 COMPUTER ANIMATION PROCESS NOVEMBER 5, 2015: ANIMATIONPAGE STORYBOARDS2.STAGING 3.SET MODELING 4.KEYFRAMING5.SHADING 6.EFFECTS 7.LIGHTING

INTERPOLATION-BASED ANIMATION CS 482 – FALL 2015 KEYFRAMES NOVEMBER 5, 2015: ANIMATIONPAGE 229

INTERPOLATION-BASED ANIMATION CS 482 – FALL 2015 ARTICULATION VARIABLES NOVEMBER 5, 2015: ANIMATIONPAGE 230

HARDWARE ISSUES CS 482 – FALL 2015 SCREEN REFRESH NOVEMBER 5, 2015: ANIMATIONPAGE 231 AMONG THE TASKS OF THE VIDEO CONTROLLER IS THE REFRESHING OF THE DISPLAY. TWO PRIMARY APPROACHES HAVE ARISEN OVER THE YEARS: PROGRESSIVE SCAN, IN WHICH SCANLINES ARE REFRESHED IN A TOP TO BOTTOM FASHION, AND INTERLACED SCAN, IN WHICH REFRESHES ALTERNATE BETWEEN THE ODD-NUMBERED AND EVEN-NUMBERED SCANLINES. THE INTERLACED APPROACH CUTS THE REQUIRED BANDWIDTH IN HALF, AND IS THEREFORE PREFERRED BY MOST TELEVISION BROADCASTERS. PROGRESSIVE SCAN REDUCES THE “COMB” EFFECT AND “TWITTER” IN THE IMAGE, AND IS THEREFORE PREFERRED BY MOST COMPUTER AND SOFTWARE MANUFACTURERS.

HARDWARE ISSUES CS 482 – FALL 2015 DOUBLE BUFFERING NOVEMBER 5, 2015: ANIMATIONPAGE 232 WHEN A DISPLAY REFRESHES FASTER THAN THE PROCESSOR CAN RENDER THE NEXT FRAME, THE SWAPPED BUFFER CONTAINS A “TORN” IMAGE (WITH SOME PIXELS FILLED WITH THE PREVIOUS FRAME’S IMAGE AND SOME FROM THE CURRENT ONE). WHEN VERTICAL SYNCHRONIZATION IS ACTIVATED, THE BUFFER SWAP IS DELAYED UNTIL THE CURRENT FRAME HAS BEEN COMPLETELY PROCESSED, ELIMINATING THE IMAGE QUALITY ISSUE, BUT THE ANIMATION SUFFERS LATENCY PROBLEMS.

HARDWARE ISSUES CS 482 – FALL 2015 TRIPLE BUFFERING NOVEMBER 5, 2015: ANIMATIONPAGE 233 BY KEEPING TWO BACK BUFFERS AT ALL TIMES, AND ALTERNATING THEIR BEING FILLED, THE FRONT BUFFER CAN BE SWAPPED WITH THE MOST RECENTLY FILLED BACK BUFFER, REDUCING LATENCY WHILE MAINTAINING IMAGE QUALITY. DOUBLE BUFFERING W/O VSYNC: DOUBLE BUFFERING W/VSYNC: TRIPLE BUFFERING:

KINEMATICS CS 482 – FALL 2015 STANDARD JOINT TYPES NOVEMBER 5, 2015: ANIMATIONPAGE 234 REVOLUTE JOINT (1 DOF) TRANSLATIONAL JOINT (1 DOF) CYLINDRICAL JOINT (2 DOF) SPHERICAL JOINT (3 DOF) PLANAR JOINT (3 DOF)

KINEMATICS CS 482 – FALL 2015 TREE-BASED HIERARCHICAL MODEL NOVEMBER 5, 2015: ANIMATIONPAGE 235

KINEMATICS CS 482 – FALL 2015 SKELETON HIERARCHY NOVEMBER 5, 2015: ANIMATIONPAGE 236

KINEMATICS CS 482 – FALL 2015 TWO APPROACHES NOVEMBER 5, 2015: ANIMATIONPAGE 237 FORWARD KINEMATICS THE MODELER ROTATES OR MOVES INDIVIDUAL JOINTS TO POSE AND ANIMATE THE JOINT CHAINS INVERSE KINEMATICS THE MODELER MOVES A HANDLE TO POSE THE ENTIRE JOINT CHAIN

KINEMATICS CS 482 – FALL 2015 FORWARD KINEMATICS NOVEMBER 5, 2015: ANIMATIONPAGE 238

KINEMATICS CS 482 – FALL 2015 INVERSE KINEMATICS NOVEMBER 5, 2015: ANIMATIONPAGE 239

KINEMATICS CS 482 – FALL 2015 CASE STUDY: TWO-LINK ARM NOVEMBER 5, 2015: ANIMATIONPAGE 240 1111 2222 L1L1L1L1 L2L2L2L2 x y 3333 4444

DYNAMICS CS 482 – FALL 2015 MASS-SPRING SYSTEMS NOVEMBER 5, 2015: ANIMATIONPAGE 241 VARIOUS MOVEMENTS MAY BE SIMULATED BY MEANS OF SPRING MODELS. MUSCULATURECURLY HAIR ENERGY STORAGE & RELEASE DURING RUNNING

DYNAMICS CS 482 – FALL 2015 COLLISION DETECTION NOVEMBER 5, 2015: ANIMATIONPAGE 242 ANIMATION FREQUENTLY REQUIRES THE DETECTION OF COLLISIONS OCCURRING BETWEEN OBJECTS IN THE SCENE. DETERMINING PRECISE COLLISIONS WITH A NON-CONVEX POLYHEDRON IS USUALLY TOO COMPUTATIONALLY COMPLEX TO IMPLEMENT DETERMINING COLLISIONS AGAINST A BOUNDING BOX OR A BOUNDING SPHERE IS COMPUTATIONALLY SIMPLE, BUT MIGHT DETECT COLLISIONS THAT MIGHT NOT BE ACCURATE AGAINST THE ORIGINAL MESH DETERMINING COLLISIONS AGAINST THE CONVEX HULL (THE SMALLEST CONVEX POLYHEDRON CONTAINING THE ORIGINAL MESH) IS A REASONABLE COMPROMISE – MORE PRECISE THAN USING A BOUNDING BOX OR SPHERE, AND LESS COMPUTATIONALLY COMPLEX THAN USING THE ORIGINAL MESH