▁A ▁framework ▁to ▁create ▁Ref actor ings ▁for ▁EM F ▁models . ▁ ▁EM F ▁Model ing ▁Oper ations : ▁A ▁tool ▁to ▁specify ▁( and ▁execute ) ▁composite ▁model ing ▁operations ▁such ▁as ▁refactor ings ▁by ▁demonstr ation . ▁ ▁W ire frame Sk etch er : ▁A ▁wire fr aming ▁tool ▁( com mer cial ) ▁that ▁is ▁driven ▁by ▁an ▁EM F ▁model . ▁EM F ▁model ▁is ▁open - source ▁and ▁is ▁available ▁from ▁GitHub . ▁ ▁Model ing ▁Framework ▁based ▁software <0x0A> </s> ▁" Props " ▁is ▁the ▁tw enti eth ▁episode ▁of ▁the ▁third ▁season ▁of ▁the ▁American ▁musical ▁television ▁series ▁G lee , ▁and ▁the ▁si xty - four th ▁overall . ▁Writ ten ▁and ▁directed ▁by ▁Ian ▁B ren nan , ▁the ▁episode ▁is ▁the ▁first ▁of ▁two ▁new ▁episodes ▁that ▁a ired ▁back - to - back ▁on ▁Fox ▁in ▁the ▁United ▁States ▁on ▁May ▁ 1 5 , ▁ 2 0 1 2 . ▁It ▁features ▁New ▁Dire ctions ▁prepar ing ▁a ▁new ▁performance ▁routine ▁for ▁the ▁imp ending ▁National s ▁competition , ▁an ▁extended ▁sequence ▁in ▁which ▁T ina ▁( J en na ▁U sh kow itz ) ▁has ▁a ▁vision ▁of ▁the ▁g lee ▁club ▁having ▁sw apped ▁roles , ▁including ▁herself ▁as ▁Rach el , ▁and ▁an ▁appearance ▁by ▁special ▁guest ▁star ▁Who op i ▁Gold berg ▁as ▁NY AD A ▁de an ▁Car men ▁Tib ide aux . ▁ ▁The ▁episode ▁received ▁mostly ▁positive ▁reviews ▁overall , ▁though ▁reaction