OpenSpace issue

[anilone]

I am trying to create FarmTown like virtual world game using SFS & OpenSpace. I am confused with few issues like

I need to allow the user to do some actions like plowing in FarmTown.
Once the Plow tool is selected in FarmTown, you can place the plowed field anywhere you like. Once place you can't walk over the ploughed filed. We can change the walkable property of tile at runtime.
But i read that changing tile property at run time is not recommended.
How the same can be achieved using OpenSpace.

Also FarmTown allow the user to walk between the plowed area. To achieve this i am planning to do it like
Reduce the tile size and consider 3x3 tiles as a single unit. put a skin with a movie clip to one of the tile, which should cover only 2X2 tiles. Other 5 tiles doesn't have any skins(just backgroud). Why i club 2X2 tiles is that the walkable area should be narrower than the plowed field. The skins movie clip will be invisible and make visible when the user plow the filed. So the 2x2 tiles will shown as plowed filed and the avatar can walk through the tiles we left (5 tiles without any skins). This will help us to simulate the FarmTown like behavior.

Is there any better option than this to simulate FarmTown? Is my approach is correct? Please advise

[Bax]

Changing tiles walkability is not possible in OpenSpace. The reason is that this would require to recalculate all the nodes of the pathfinding algorithm, with a major impact on performance and unpredictable issues with avatars already moving around when this happens.