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Shear & Perspective. CS5600 Computer Graphics Rich Riesenfeld Spring 2006 (Sp2014 edits by T. J. Peters). Lecture Set 7. 3D Shear in x -direction. 3D Shear in x -direction. 3D Shears : Clamp a Principal Plane , shear in other 2 DoFs. Shear in x . . then , y :.
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Shear & Perspective CS5600Computer Graphics Rich Riesenfeld Spring 2006 (Sp2014 edits by T. J. Peters) Lecture Set 7
3DShear in x -direction Utah School of Computing
3DShear in x -direction Utah School of Computing
3D Shears: Clamp aPrincipal Plane, shear in other2DoFs Utah School of Computing
Shearinx..then, y: Utah School of Computing
3D Shear iny -direction Utah School of Computing
3DShear iny -direction Utah School of Computing
3DShear inz-direction Utah School of Computing
3DShear inz Utah School of Computing
3DShear inz Utah School of Computing
ShearInverse Utah School of Computing
ShearInverse Utah School of Computing
Double Shear in x and y Utah School of Computing
Ex: a=0.5and b=1.0 Utah School of Computing
Shearinx..then, y: Utah School of Computing
Shearinx .then, y: Utah School of Computing
Shears in x and y donotCommute Sh in x(a=½) , then Shy(b=1) Sh iny(b=1) , then Sh inx(a=½) Utah School of Computing
Shearin x then in y Utah School of Computing
Shearin y then in x Utah School of Computing
Results Are Different y then x: x then y: Utah School of Computing
What is “Perspective?” • A mechanism for portraying 3D in 2D • “True Perspective” corresponds to projection onto a plane • “True Perspective” corresponds to an ideal camera image Utah School of Computing
“True” Perspective in 2D (x,y) h p Utah School of Computing
“True” Perspective in 2D Utah School of Computing
“True” Perspective in 2D (x,y) h p Utah School of Computing
“True” Perspective in 2D Utah School of Computing
“True” Perspective in 2D Utah School of Computing
Geometry Same for Eye at Origin Screen Plane (x,y) h Utah School of Computing
Values below 0? (x,y) h p Utah School of Computing
“True” Perspective in 2D Utah School of Computing
“True” Perspective in 2D Utah School of Computing
“True” Perspective in 2D Utah School of Computing
Viewing Frustum Utah School of Computing
What happens for large p?” Utah School of Computing
Projection Becomes Orthogonal: “Right Thing Happens” (x,y) h=y Utah School of Computing
The End (Modified) Transformations II Lecture Set 7x