I've downloaded MOO Mapper and it's a fine product, especially considering the price.
I decided to get started by creating a new road from the first savepoint in GTA3. I've used road pieces from the area near the savepoint and created my own IPL file to house them. I've saved the IPL and it's linked from GTA3.dat OK.
However, when I try and load the game the progress bar gets about 75% of the way through and then freezes.
I read about .COL files and whatnot in this game but I'm unsure if I need one (I've not added any new models, textures or anything - just used the road pieces already declared in the game). I wouldn't know how to construct one for the road pieces on the new map I've created.
I've been doing some reworking on the road today and maybe when I tried it last night I didn't give the duplicated objets any names. That might have been why it was crashing last night. I'm going to give it a try when I get home and see if the duplicated-objects-now-with-proper-names might work better.
I guess I might have already fixed the problem, but I figured I'd throw this out there in the hope someone can confirm or deny something that I'm doing wrong before
I get home.