The youngest movie­go­ers today do not, of course, remem­ber a time before visu­al effects could be cre­at­ed dig­i­tal­ly. What may give us more pause is that, at this point in cin­e­ma his­to­ry, most of their par­ents don’t remem­ber it either. Con­sid­er the fact that Steven Spiel­berg’s Juras­sic Park, with its once impos­si­bly real­is­tic (and still whol­ly pass­able) CGI dinosaurs, came out 32 years ago. That may put it, we must acknowl­edge, into the realm of the “clas­sic,” the kind of pic­ture whose enter­tain­ment val­ue holds up despite — or because of — the qual­i­ties that fix it in its time. Equal­ly spec­tac­u­lar but longer-can­on­ized clas­sics pose a greater chal­lenge to the imag­i­na­tions of young view­ers, who can hard­ly guess how they could have been made “before com­put­ers.” After see­ing the notable exam­ples pro­vid­ed in the new Pri­mal Space video above, they’ll cer­tain­ly under­stand one thing: it was­n’t easy. Even a seem­ing­ly sim­ple effect like the pen float­ing loose through the zero-grav­i­ty cab­in in 2001: A Space Odyssey required no small degree of inge­nu­ity. We might …