Course 10 Shading. 1. Basic Concepts: Radiance: the light energy. Light Source:

Transcription

1 Cour 0 Shadg

2 Cour 0 Shadg. Bac Coct: Lght Sourc: adac: th lght rg radatd from a ut ara of lght ourc or urfac a ut old agl. Sold agl: $ # r f lght ourc a ot ourc th ut ara omttd abov dfto.

3 llumato: lght rg radatd or rcvd o a ut ara of urfac. For a ot lght ourc L co d d ## whr th radac of lght ourc th drcto ; du to co th forhort of ffctv ara of th urfac atch th radato drcto.

4 Surfac: B-drctoal rflctac dtrbuto fucto BDF: BDF of a urfac th rato of rg radatd from a urfac atch om drcto to th rg arrvg at th urfac from om drcto. BDF f ; Whr --- cdt agl; --- mttg agl

5 adac rflctac : Th th brght of a objct urfac that ou look at. d d f L # # co ; $ $ L

6 magg : Aum that th rradac at a ot XY of a mag la ual to th radac from a corrodg urfac atch.. EXY Lz L Th dcat that th trm of brght tt ad gra-lvl wll hav th am mag a rradac for a mag. Not: radac out-gog rg rradac gog rg

7 . Surfac flctac Lambrta urfac Dffu urfac mcro: rough macro: mooth Df. Lambrta urfac a kd of urfac that rflct cdt lght uall all drcto rgardl th drcto of cdt lght. A Lambrta urfac aumd ot to aborb a cdt llumato. BDF f è ö ;èö

8 Lè ö 0 coè whr llumato of cdt lght cdt agl to urfac. mark: For a Lambrta urfac t brght rcvd b a vwr do ot rlat to th oto of th vwr. But th brght trogl rlatd to th drcto from whch th lght llumatd to th urfac.

9 Scula urfac mrror 3 Combatoal urfac: Surfac wth rflctac btw Lambrta ad cular urfac: Whr BDF f ; L BDF # # -----wgh factor $ % $ # %# % co $ % $ # %# % co

10 3. Sha from hadg Hor970 Aumto: Lambrta urfac Paralll lght ourc from kow drcto Orthograhc rojcto for mag magg: gv th codto of lght ourc ad objct urfac 3D th tt of ach l mag la ca b uul dtrmd. Quto: f a mag gv ca w valuat th tructur of th 3D urfac?.. ca w fd th urfac ormal at ach urfac ot? How about th llumato of lght ourc?

11 Surfac Ortato : Lt a 3D urfac b zz th Dot Surfac ormal z z z z z v v

12 Not: ad ar th fucto of 3D ot z at a urfac. Udr th aumto of orthograhc rojcto ad ar alo th fucto of XY of mag.. XY XY Quto : How to dtrm th two fucto from mag clu?

13 flctac ma Aum: Lambrta urfac 0 E L co Wh mag tt ormalzd b th E ma{ E ; mag la} co O aothr had for a 3D urfac lt b urfac ormal; Lt lght th b cdt drcto of

14 Whr calld rflctac ma of a 3D urfac. To olv for ad w ca u varato to mmz [ ] ovr mag la: m [ ] dd Not that th a ll-codtoal roblm to olv for fucto ad w forc mooth cotrat: 0 0

15 Thu th mmzato bcom $ m {[ # ] [ } dd dcrt mag: j j j 4 j j j j j j j j Lt 0 0

16 W gt So 0 ] [ ] [ # 0 ] [ ] [ # ] [ # ] [ #

17 Sc ad ar comutd from th valu of th ghbor l of tratv mthod hould b ud to olv for ad. For a Lambrta urfac } ] {[ # } ] {[ #

18 mark: aumd cdt lght drcto kow. th choc of tal valu of ad mortat to gt a covrgc at global mmum.

19 4. Photomtrc tro Aum: Fd camra oto Lght ourc locatd at 3 dffrt oto to urfac at ach oto O mag obtad. Lambrta urfac v Orthograhc rojcto for thr mag. Lt cdt drcto b : z 3

20 Surfac ormal: ukow mag: ormalzd mag: From rflctac ma of Lambrta: Wrt Th w hav. Th a lar uato whch ca b olvd b 3 3 S # $ $ $ % & # $ $ $ % & z z z S # $ $ $ % & 3 S S

21 Furthr radg: tmato of urfac ortato w d to kow th drcto of th llumato from lght ourc frt How to tmat th drcto of lght ourc from a tt mag? ---- Ptlad mthod ---- L & ofld mthod ---- Ta ad Shah mthod ---- Zhg & Chllaa mthod All aum that th 3D urfac a art of har th tag of tmato of llumato drcto of lght ourc.