LONDON , England ( CNN ) -- Let 's say you were making a film . Which do you think would be harder ? A . Coordinating a mass alien invasion B . Invoking tidal waves and tornadoes C. Telling a prehistoric love story . Roland Emmerich and Steven Strait ( D'Leh ) discuss a scene shot in Namibia when the young hunter discovers farming for the first time . For Roland Emmerich , the answer is C. He says `` 10,000 BC '' is without a doubt the most difficult film he 's ever made . It was n't the time-consuming graphics that took the greatest toll , nor the need to re-record a lot of the dialogue . No , the most challenging aspect of this film was , um , the weather . `` You 're obsessed with the weather channel , '' Emmerich says , of the duration of filming . `` Ninety percent of this movie was [ shot ] outdoors . '' Producer Michael Wimer : `` It seemed like every time we needed sun , we 'd get rain , every time we needed green landscape , we 'd get snow . There we just got a series of curve balls , the weather is really fickle . '' Emmerich says : `` It 's like somebody did n't like 'Day After Tomorrow ' and was like : 'We showed him . ' '' Filming started in the wintry peaks of New Zealand 's South Island , then moved to Cape Town in South Africa , then further north to the desert of Namibia . But it was n't just the weather that tested the filmmakers ' skill , patience and stamina . see scenes from the film » . Prehistoric beasts . Visual effects supervisor Karen Goulekas started working on project two years before principal filming even started . She broke down the script to see what could be done , and what could n't , then set about the bringing prehistoric animals back to life . Perhaps her biggest challenge was to create the film 's `` terror birds '' , flightless predators with huge beaks that hunt like sharks , suddenly piercing through long grass to snatch their prey before disappearing again . The birds were based on a number of images . During filming the terrifying bird was actually a blue head on a stick . `` It 's been an experience , '' says Camilla Belle ( Evolet ) , `` I 've never worked with blue birds before and all that fun stuff . '' see D'Leh take on the terror birds » . Sets . After seeing off all manner of prehistoric threats , the film 's hero D'Leh and his assembled army are awestruck by an immense 'lost ' civilization dominated by pyramids that reach up into the sky . Not only did the filmmaker build the pyramids ( at Dune 7 in Namibia ) , they also built miniature replicas of the pyramids , 'God 's palace ' , the slave quarters and the Nile River . The buildings were made in Munich before being transport to Namibia in 15 sea containers . Once assembled , they covered an area of 100 square meters . see the pyramids during a battle scene in the film . Costumes . What to wear when you live in 10,000 BC ? Presumably there was n't much choice in those days , which gave the film 's costume designers plenty of scope to use their imagination . They dressed the Yagahl tribe , or mammoth hunters , in antelope fur and hides in place of mammoth . But the weather was so cold during filming that some actors also wore thermals underneath . The final scenes required dressing 800 extras as slaves . Each costume had to be handmade to conceal the stitching . Says costume designer Renee April : `` We had an army in the workshops making beads from clay and glass and sewing them onto the costumes as well as making the fabric and headdresses . '' 1000 sandals also had to be made to order . Sound . Most of the dialogue in the film had to be recorded not once , but twice . Peter Gleaves , an Automated Dialogue Replacement Mixer at De Lane Lea Studios in Soho , London explains : `` The original sound sometimes has background noises -- wind machines , sounds of cars and aeroplanes -- that in a production like '10,000 BC ' you do n't want to hear . So to get rid of them you have to get the actors to redo all their lines , or most of their lines . '' Steven Strait was summoned to London to re-record some of his dialogue . When the Revealed cameras dropped in he was working on his grunts . see Steven Strait grunting and panting ! `` It 's an action sequence , '' Strait explains , `` so there are very few words . It 's mostly just running and jumping and grunting and doing all sorts of strange sound effects that are going to look incredibly weird in this room , but hopefully it works in the film . '' see the final product of Steven 's grunting , the mammoth hunt .
Emmerich developed obsession with the weather during filming of ` `` terror birds '' was shot in Munich the Nile River , Munich and Namibia . Other challenges include creating film 's 'terror birds ' , shark-like predators . Miniature pyramids , 'God 's palace ' , made in New Zealand 's then shipped to Namibia .