It's the general picture, different courts may invoke different past verdicts for similar cases, in case a lawsuit was raised. Most developers simply let it go as some moddings are more benefits to their products than harms, but you shouldn't automatically assume what you're doing is within your rights. My suggestion, go with the crowd. As someone who'd been pirating stuff over 10 years, yaagrrhhh.

PS: Also a link reference for http://en.wikipedia.org/wiki/Reverse_engineering. It's a touchie subject, developers built plenty barriers to protect themselves. Not sure at your country, but if I'm trying to make a patch for someone else's software my government would sue me for 10 millions just to feed its treasury.

I've been trying tell people this for a long time: Dwarf Fortress is not a game <_<

Here's why:

• You can't win
  
• You don't play the game as much as you just sit around and hope your dwarves don't [censored] things up
  
• It's bat[censored] insane
  
• It's more difficult to play than trying to code an OS in Brain[censored] (a joke programming language, google it at your own risk)
  
• I hate Dwarf Fortress

On the contrary, you should most definitely assume such things are within your rights until you receive some kind of indication otherwise. Otherwise you'll spend so much of your life walking on eggshells, trying to avoid even the remotest possibility of drawing someone's ire, that you'll never manage to accomplish anything. If there's a game you like and you want to try your hand at tweaking it or creating new content for it, go for it! Mod the [censored] out of it. If for some reason the dev or publisher objects and fires off a C&D to you, then that's the time to evaluate your next course of action (which could range from directing your modding efforts to a different game, or telling them that you're well within your rights and they can shove that C&D up their ass). But to hamstring yourself from the very start over concerns about the incredibly remote possibility someone will object to an activity that for all appearances is well within one's rights... well, all I can say is that I feel great pity for anyone who's worked themselves into such a horrible mindset.

No you shouldn't assume that way. But does that mean it's a reason to hold you back? Not at all. I fully support your attitude in modding, but the law is the law. Censor the law I say. Do what you want cause a pirate is free!

How do you understand the workings of an OS if you don't perform some forms of reverse engineering in first place? Is it against the law? yes, but will you do it? Hell yes! Will you fight for it if someone is trying to sue you for that? Hell yes you should! The net is tossed to catch the bad fish, and you are under the fish net, can you assume you are out of the net? No. If the law is so strict and dead straight there wouldn't be a need of lawyers.

So yeah, if you ask is modding illegal. To a certain extend mostly yes. Will you stop modding for this reason? You shouldn't. It's stupid to hold back for this reason. If you have harmed the interest of its author unwillingly, they'll notifying you in black and white asking you to stop before resorting to the court. Were there cases which they sue people after you have done these for extended period of time? Yes there were verdicts with the defendants being found guilty.

Is it against the forum rules to encourage illegal activities speaking of unauthorised modding of software? Yes. So how far would you go? It is a moot point (not for the moderators tho), but you get my drift. Are we under the net moderators had casted on us? Yes. Is it safe to discuss this matter? Well... they didn't complain. Yarrggghhhh!

So what's best for OP to ask is not what software to mod, but how to mod.

You seem intent on missing the point that from all appearances modding is perfectly legal. Rather, you seem so concerned about the remote possibility that under certain tortured interpretations of the law it just might be illegal that you want to just dispense with any ambiguity and fully declare it illegal. All I can say is that I'm sorry you've adopted such a horrible mindset, and that I hope one day you manage to break out of it.

It's an in-depth interactive fantasy world simulator.

Also the earlier Doom games which still have a decent modding community.

Confused now. Just wanted to mod a bg game

Then do so and don't worry about anything else. Lots of modding has occurred for the BG games for many years with absolutely no issues at all. So knock yourself out.

And have you personally done this?

Any that give you the source code ?

Wrong thread.

I've used mods for the BG games (as well as other Infinity Engine games). I haven't tried my hand at making mods for them, just out of a lack of interest in doing so.

Me too. My current installation of Baldur's Gate 2 is fairly heavily modded:

Widescreen Mod
BG2 Fix Pack
BG2 Tweak Pack
Banter Pack
Quest Pack
Dungeon B Gone
Unfinished Business
Ascension, Redemption, Turnabout
Colours of Infinity

Good stuff.