I want to build a sim house from a blueprint of a real house (sounds crazy, right?) and I want to get it as close to the real one as possible. I have tried this and the house that I build on the sims doesn't come out the same. So, my question is: how many feet does a square replecate in the sims? I thought that it might be two feet, but that's not right. Four squares doesn't equal eight feet. If anyone knows it would be greatly appreciated.
Thanks, in advance.

In my experience, a grid square in the Sims is roughly a meter (about three feet) in real life.

Well, given a standard door frame is 900mm and in the sims it is 1 square wouldn't that make it 1 square = 3 feet (1 yard)?

As long as you keep the same ratio your entire project it shouldn't matter whether 1sq = 1yd or 1sq = 1m.

I do a 1:3 ratio as several others mentioned, but I fudge on things a bit. Sims don't do well in two tile rooms. So if there is a two tile space, I will either move the room around or enlarge it a little. Sometimes I'll just merge the room into another. I always give the front porch at least three tiles because I have lots of parties at my house and I found that two tiles will cause traffic jams and groups of sims will have difficulty getting in and out of the house. I also usually get rid of hallways and just merge the floor space into other rooms. Sims don't seem to appreciate hallways.

Building from RL floor plans is a fairly common practice among builders. I generally take into account the size of the lot and what I want to put in there to determine the ratio of the house. If you are using a small lot and want to add things such as a pool, deck, garden or whatever, the house needs a smaller ratio to the plan. Larger lots with the same additions will allow for a larger ratio. As Zokugal said, keep the whole project at the same ratio.

When building "traditional" homes, I tend to consider the size & layout when it comes to the roofing. The roof can make or break a build. EA's auto roofing is a disaster so I try to modify the plan so I can add roof sections that flow nicely and still allow the house to play well.

For me, it comes down to tweaking the plan ratio so that it not only looks good from the outside but also flows well in game.

Thanks, guys. All of your posts have been very helpful....especially cameranutz2 and Zokugal.

I normally do 1:2 (feet). It comes out WAY too small if I do it any bigger.

I usually figure a square at 30 inches (2.5 feet). This seems to render reasonably sized lots and rooms. But it's just a starting point. You have to make the lot work right.