▁terrain ▁features ▁like ▁cl iffs ▁and ▁c aves ▁were ▁made ▁by ▁generating ▁positive ▁and ▁negative ▁spaces ▁within ▁the ▁cube ' s ▁mapping , ▁and ▁incorpor ating ▁those ▁into ▁the ▁spher ical ▁transformation . ▁ ▁The ▁development ▁team ▁built ▁the ▁planet ary ▁feature ▁generation ▁system ▁at op ▁this ▁where ▁they ▁would ▁first ▁hand - create ▁core ▁structures ▁and ▁the ▁art ▁associated ▁with ▁those   – ▁such ▁as ▁a ▁basic ▁ske leton ▁and ▁skin ▁for ▁a ▁creature   – ▁and ▁then ▁allow ▁the ▁algorithm ▁to ▁make ▁random ized ▁changes ▁to ▁that , ▁as ▁to ▁make ▁a ▁wide ▁variety ▁of ▁cre atures , ▁m im ick ing ▁the ▁divers ity ▁of ▁species ▁resulting ▁from ▁evolution ▁on ▁Earth . ▁They ▁made ▁sure ▁the ▁elements ▁of ▁this ▁generation ▁process ▁reflected ▁the ▁setting   – ▁cre atures ▁and ▁plants ▁inhab iting ▁a ▁planet ▁that ▁contained ▁blue - col oured ▁min er als ▁would ▁be ▁t int ed ▁blue ▁as ▁well . ▁The ▁generation ▁system ▁uses ▁determin istic ▁parameter ised ▁equations ▁and ▁algorithms ▁previously ▁developed ▁by ▁bi olog ists ▁and ▁phys ic ists ▁that ▁can ▁m im ic ▁a ▁vast ▁array ▁of ▁natural ▁forms ▁and ▁shapes . ▁For ▁example , ▁the ▁engine ▁uses ▁L - system s , ▁f ract al ▁equations ▁developed ▁by ▁Arist id ▁L inden m ayer ▁in ▁ 1 9 6 8 ▁that ▁can ▁create ▁structures ▁that ▁res emble ▁many ▁alg ae ▁and ▁plant ▁life forms . ▁This ▁is ▁couple d ▁with ▁engines ▁like ▁Speed Tree ▁to ▁create ▁additional ▁variety ▁to ▁the ▁fl ora . ▁