Shader Daim Ntawv Qhia Tawm
Tshaj no nyob rau hauv lub kaum ntse ntse gadgets, zaub mov tsis tshua ua rau ntau qhov kev txiav txim zoo, tab sis nws tshwm sim rau kuv lwm hmo thaum kuv digging pem pab tswv yim rau ua txiv qaub kua txob qaib tias kuv tuaj yeem pib ua ib qho txawv ntawm daim ntawv qhia - shader zaub mov txawv .
Tag nrho "cookbooks" tau muab sau rau cov ntaub ntawv thiab cov duab ntxoo hauv Maya, UDK, 3DS Max, Vray, thiab lwm yam.
Nws yog ib yam dab tsi ntau ntawm pib tshiab muaj teeb meem nrog, thiab rau qhov laj thawj zoo! Tweaking ib qho arrays ntawm arcane tsis zoo li "specular zog" thiab "diffuse luj" rau kev sim siv cov khoom siv hauv ntiaj teb xws li ntoo, iav, pob zeb, lossis cov nplais pobzeb tsis ua haujlwm yooj yim.
Yog li, peb nyob no.
Pib ntawm ambient occlusion , peb mam li pib ua kom paub qee cov ntawv teev npe rau tej yam khoom siv hauv ntiaj teb uas nyuaj rau cov ntsia thawv. Peb mam li siv Maya hauv no series, tab sis peb yuav tseg rau hauv Unreal Development Kit ib lub sij hawm los yog ob. Peb zoo siab txog qhov no thiab xav kom koj kawm ntau npaum li sau thaum koj nyeem nws!
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Ambient Occlusion yog dab tsi?
Tsis txhob cia lub npe ruam koj-ambient occlusion yog ib qho zoo nkauj ncaj qha khoom tsim tsa, thiab nws yog ib qho tseem ceeb heev.
Tsuas yog AO siv (zoo nkauj tag nrho) rau kev ua haujlwm tawm hauv kev ua hauj lwm, nws tseem pheej siv los ua lub hauv paus thiab ua duab thaij duab vim nws pab tsim cov kev nthuav dav thiab "av" hauv qhov chaw los ntawm sib txuas cov duab ntxoov ntxoo .
Ambient occlusion yog ib daim ntawv ntawm tus kheej shading cov ntaub ntawv, nws txhais tau tias nws tseem ua haujlwm txawm tias tsis muaj teeb pom kev zoo hauv koj qhov chaw. Nyob rau hauv kev tshawb xav, nws yog ib txoj kev ntsuas ntawm lub ntiaj teb illumination rudimentary, thiab txhais tau hais tias kom ntsi xws li txoj kev kaj nrig nyob ib ncig ntawm chav tsev los yog ib puag ncig.
Kev ua rau lub cev tsis muaj zog yuav ua rau lub ntsej muag "tsaus muag" tsaus nti nrog ob qho chaw los yog qhov chaw (ze ntawm chav tsev, cov khoom hauv qab, cov ntsiab lus zoo, thiab lwm yam). Ambient occlusion dluab tau qee zaum hu ua "av nplaum renders" vim tias lawv tus qauv sib piv rau kev ua qauv av nplaum.
Ntawm no yog ib cov qauv kuv ua rau lub rooj cob qhia xyoo tas los no uas siv cov ambient occlusion qhia tawm ntawm daim qauv (cov tswvyim ua rog los ntawm Diego Almazan).
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Tsim ib qho Ambient Occlusion Shader:
Tsim ib qho teeb meem me me rau cov duab pom kev yooj yim yog yooj yim zoo nkauj, thiab tsis tas yuav tsum muaj UVs, kev ntxhib los mos , los sis teeb pom kev zoo.
Muaj ntau txoj hauv kev los ua kom muaj kev sib txawv rau me ntsis, tab sis ib qho kuv mam li qhia ntawm no yog qhov zoo thiab ncaj nraim, tsuas yog ib qho ntawm Mental Ray ntawm thiab ib yam khoom siv Lambert.
Ntawm no yog piav qhia luv luv-ib-theem.
Qhib tau lub qhov rais Hypershade thiab tsim cov ntaub ntawv tshiab Lambert.
Muab cov ntaub ntawv lub npe-Kuv feem ntau siv tej yam zoo li ambientOcclusion_mat .
Ob nias qhov khoom los qhib nws cov khoom siv. Qhov no yog qhov uas peb yuav ua rau feem ntau ntawm cov ciaj ciam rau tus shader.
Los ntawm lub neej ntawd cov khoom diffuse xim yog nruab nrab grey, tab sis peb tsis xav kom peb cov highlights yuav tawg tawm, ces peb nyob nraum yeej xaub cov xim nqis mus rau qhov kawg ntawm ib tsos tsaus tsawv ntawm cov spectrum. Peb siv 0, 0, .38 rau HSV tus nqi ntawm cov yeeb yam xim , tab sis qhov no yog qhov teeb meem ntawm tus kheej nyiam.
Qhov ntxiv mus peb yuav tsum ua yog plug lub ambient occlusion node rau hauv cov ntaub ntawv cov incandescence attribute.
Nias lub voj voog khawm ntawm ib sab ntawm lub tswv yim. Qhov no yuav coj mus rau qhov render node qhov rai.
Hauv qab Mental Ray tab, nyem textures thiab nrhiav mib_amb_occlusion hauv daim ntawv. Nyem nws, thiab cov ntawm yuav qhib rau hauv tus cwj pwm editor ntawm sab xis ntawm koj lub vijtsam.
Koj yuav tsum pom cov npe ntawm cov cwj pwm-cov tseem ceeb rau peb yog cov qauv, ci / tsaus, sib kis, thiab ntau qhov chaw, tab sis tsuas yog peb yuav hloov yog tus naj npawb ntawm cov qauv.
Nyob rau hauv lub lag luam tawm ntawm qhov chaw ua haujlwm, cov naj npawb ntawm cov qauv tswj cov suab nrov nrov hauv koj lub kav.
Tshem tawm ntawm 16 los yog 32 yuav tsum tau grainy kuj, thaum nce lub nqi rau ib yam dab tsi zoo li 64 lossis 128 yuav tshwm sim heev. 32 piv txwv zoo rau kev kuaj, tab sis yog tias kuv npaj rau qhov uas qhia cov duab kuv mam li siv feem ntau ntawm 64 los yog 128.
Sim ua ob peb yam ntawm cov qauv sib txawv kom tau ib qho kev xav rau qhov txawv - tej zaum koj yuav pom koj zoo li lub ntsej muag ntawm qhov kawg ntawm lub spectrum.
Ntawm no yog ib qho kev sib piv duab kuv tau siv qhov chaw ua si sab nrauv kuv sim ua qauv zoo rov los uas qhia qhov sib txawv ntawm Maya luj kav, thiab ambient occlusion renders nrog 64 thiab 128 samples. Pom ntau npaum li cas zoo li daim duab zoo nkaus li ua rau muaj kev kub ntxhov?
Koj tuaj yeem ua si ncig nrog lwm cov yeeb yam yog tias koj xav tau:
Kaj thiab maub tswj qhov yam tsawg kawg thiab qhov siab tshaj plaws hauv koj lub kav. Yog tias koj pom tias koj cov ntsiab lus nrov nrov los yog koj ntxoov ntxoo ntxhias, koj tuaj yeem siv cov sliders los txhim kho. Tshaj tawm thiab max nrug yuav hloov cov kev poob / cais tawm ntawm koj lub teeb thiab tsaus qhov tseem ceeb.
Koj mus! Hopefully koj twb kawm me ntsis txog ambient occlusion thiab li cas nws yuav siv tau raws li ib qho kev nthuav qhia zoo rau koj 3d scenes. Qhia rau kuv paub hauv lub blog yog tias koj muaj lus nug dab tsi!