I don't think the cauldron will be sit on the ground like in 2007, it would be horrible those protection net around the sacred flame.
I guess they'll build a tower or something like Seoul did in 1988.
Another chance is put the cauldron close to the roof like Beijing, but not so that close, after all we can't see the roof burning.
......
I have some news about Rio 2016 OC.
Italian Marco Balich, who's in charge of the Rio 2016 OC executive production, was interviewed last week in Sochi by a brazilian newspaper Lance! He's also producing this WOG closing ceremony and Paralympic's ceremonies. Look at his statement:
- O estádio foi concebido há muitos anos e apresenta inúmeros desafios do ponto de vista da produção - afirmou o italiano Balich.
-The Maracana Stadium was built many years ago, so this make the ceremonies' production very challenger because of the stadium's limitations.
According to him, the process to choose an artistic and criative director has been started already.
the Balich's complete interview
http://www.lancenet.com.br/rio2016/Produtor-cerimonias-Olimpiada-dificuldades-Maracana_0_1081691828.html