Question: Is there any way to alter just the roads, while leaving the neighborhood decorations intact?
Update:I have written a small program to replace the roads in one neighborhood with the roads from a second neighborhood. It is available at:
http://www.modthesims2.com/showthread.php?t=279992-----------------------------------------------
Thoughts leading up to this utility:
It would seem that the roads and decorations are stored together in the same record, but in different arrays within that record:
http://www.sims2wiki.info/wiki.php?title=NHTRSimPE extracts the entire record, so it can't be used to separate the roads from the decorations. I can think of a couple of things that might work:
1) Use a proper hex editor to add roads to the road array, while leaving the decorations intact.
2) Write a program for the same. It's probably not too difficult if you know how to program, except for the UI on how to specify where you want the roads.
It's really a shame that EA left out road editing when they added the ability to edit the neighborhood terrain.
Update: I just thought of an easier solution...
Instead of trying to write a program which has a special UI for specifying modifications to the road structure, you could use the existing "adding roads to a neighborhood" technique to add roads using SiimCity 4. Then, instead of merging the new neighborhood terrain into the old neighborhood using SimPE, it would be fairly simple to write a program which would take the two neighborhood packages (old neighborhood with decorations and new neighborhood with roads) and perform a merge on the individual "roads" array within the NHTR record.
Of course, this still doesn't resolve the problem of how to get the original SC4 file for the neighborhood, if EA didn't ship it with the game. But, it would work for all neighborhoods with a corresponding SC4 file.
Oh, and the wiki is wrong. Tree entries are 38 bytes each, not 37. Road entries are 124 bytes each, instead of 123. Update: the wiki has been fixed, but I suspect that the other structures may also have incorrect sizes.