The ball never landed either on rough or fairway in Harrys shot. Same problem with Olympic in hole 2, 5 and several other holes.
Of course WGT can not match accurately trees, but it is clear, especially at Olympic that ball hits "something" which is not visible in the replays.
Those "collidable" objects are simply surfaces the balls has contact with; fairways, rough, brush, sand, trees, cement paths or any other solid object make the ball bounce in WGT. Each collidable object has its own properties and will bounce the ball differently.
Any other surface than trees can be matched accurately because WGT uses a territory scanning based on GPS coordinates. WGT founder talks about those architectonic technical data used to match the HD pictures with the grid created out of those scannings.
There are several full 3D objects in the game, (not planar or 2D) including, avatars, equipment.....flags and trees.
Eric
edit...forgot to mention FRINGE bounce, which WGT has it very wrong and therefore very unrealistic.
We all have seen approaches landing on fringe and seeing the balls being launched forward several or many feet.......inexplicable & unrealistic.