we had only one day and a 3/4 for making assets and create some scene with them. the other quarter of the day was used to see how speedtree works.
the landscape and houses were also all done from scratch. we only used some few assets from UT
the task was to place objects in an urban area. there were some placing rules they had to follow and it worked out quite good.
also it can be seen, that weather and atmosphere effects are essential for a believable scene