▁a ▁demo ▁exists ) ▁▁ ▁Source ▁release ▁and ▁further ▁develop ments ▁ ▁On ▁June ▁ 2 0 , ▁ 2 0 0 0 ▁( acc ording ▁to ▁his ▁website ) ▁Ken ▁Silver man ▁released ▁the ▁Build ▁engine ▁source ▁code . ▁▁ ▁Early ▁days ▁ ▁Version ▁ 2 . 0 ▁of ▁Matt ▁Sa ett ler ' s ▁ED u ke , ▁a ▁project ▁to ▁improve ▁Duke ▁N uk em ▁ 3 D ▁for ▁mod ders , ▁was ▁sent ▁to ▁ 3 D ▁Real ms ▁for ▁pack aging ▁shortly ▁after ▁the ▁release ▁of ▁the ▁Build ▁source , ▁leaving ▁Duke ▁N uk em ▁ 3 D ▁the ▁pre - built ▁libraries ▁that ▁ 3 D ▁Real ms ▁had ▁used ▁with ▁the ▁original ▁Duke . ▁( B oth ▁Duke ▁N uk em ▁ 3 D ▁and ▁ED u ke ▁were ▁still ▁closed - source ▁at ▁this ▁point .) ▁ ▁With ▁the ▁ 2 . 1 ▁private ▁bet as , ▁Sa ett ler ▁worked ▁towards ▁integr ating ▁Silver man ' s ▁build ▁source ▁into ▁the ▁Duke ▁source ▁code , ▁but ▁the ▁project ▁f izz led ▁out ▁before ▁producing ▁anything ▁more ▁than ▁some ▁very ▁bug gy ▁private ▁bet as . ▁A ▁few ▁total ▁conversion ▁teams ▁for ▁Build ▁games ▁decided ▁to ▁work ▁from ▁Silver man ' s ▁Build ▁code ▁directly , ▁and ▁an ▁en hanced ▁version ▁of ▁the ▁Build ▁editor ▁known ▁as ▁Map ster ▁was ▁also ▁developed . ▁ ▁It ▁was ▁claimed ▁at ▁the ▁time ▁by ▁many ▁on ▁the ▁ 3 D ▁Real ms ▁for ums ▁that ▁it ▁would ▁be