So I've seen folks talk about building houses in the Sims 2 (Or 3 or 4, though I only have Sims 2) based on blueprints they found on line. My question is how would you convert stuff like a room labelled as 12'x10' to Sim Units? Are the squares directly able to represent something in either the Imperial or Metric system, or do you just have to do it by eye?

I'm building some houses in a neighborhood in the styles from 1910-1930 in America but I am not sure how to translate the measurements into Sim Units. Any help would be appreciated.

Personally, I scale the real measurements down to tiles, or scale tiles up to measurements.

I use the furniture to measure out a room
Single beds in TS2 are 3x1 tiles. I have a single bed in my bedroom that goes wall-to-wall (I have a small bedroom - very cosy), so my real life bedroom would be 3 Sim tiles wide. In imperial measurements, it's roughly 6 1/2 to 7ft wide, because the bed is a bit bigger than my height.

Of course, if I was to make my house in TS2, I'd have to make my bedroom that bit bigger due to routing in the game.

Yeah, I would do tiles too. We tend to smallish houses in the UK. A typical bedroom would hold a double bed, wardrobe, maybe a dresser. I generally do 1 tile = 2'. A 10'x12' room, five tiles by six, would have room enough to place the bed and leave room for an entrance at the side then space at the bottom for the wardrobe. Something like that. Of course, not all rooms are square. I think I've had a fair amount of success building to floor plans and I found that works more or less though I tended to concentrate on getting the right look first and foremost. I think the primary things to think about are playability and getting the character of the house. This often means compromises and adjustments. Course, you might not agree with my definition of success. I had to adapt the floor plans of the house I built in the picture but I was fairly pleased with the outcome. I think the architect's picture and actual build match quite well. That's an old build BTW (I've not done plan-building for a while) and I think I'd do better for windows and other features now. I've always liked that house though - very playable.

I can't cope with numbers at all, so what I find useful, if building to a floorplan instead of around the furniture, is to think in terms of "lights" rather than measurements. A "light" is the visual unit of a single normal-sized window or door in the floorplan. It is possible for a house to have individual windows, sidelights for example, that are half a light wide, or less, in relation to the scale of the house, but generally speaking if you look at the front elevation you'll see at once which units are defining the lights for the building.

Most sims houses will have lights that are one tile wide, though ones that use windows and doors centered on two tiles will have two-tile wide lights. So your first important decision will be which windows and doors to use, and ensuring that they work well together. Once you do that, you count the lights across the front and draw your front foundation or wall line to suit, and scale the rest of the house appropriately. Maxon's example above show how this works - you can see how the blank wall spaces and corners are proportioned according to the lights established by the windows.

This works less well with modern tract houses, a great deal of the ugliness of which is down to their not incorporating a need to get exterior light into the house as a design criterion; but for the period you're using it should work well enough.

Remember also that sim needs are not human needs, so you'll have to tweak the interior floorplan to suit them. They need space to pass each other in the hall a lot more than they need a closet in every room, for example.

When I build a house to a house plan online I print it out and use things such as windows and doors, sinks, stoves and bathtubs to guesstimate size. These things are all worth 1-2 tiles in a sim house. If the plan shows a double window, I use a two tile window or perhaps 2 singles or 3 singles if need be. You also have to judge room size. A bedroom needs a minimum amount of tiles to fit a double bed. Sometimes plans might be too small (hallways) or be too large (bedrooms and bathrooms) Some rooms are redundant unless you use cc (laundries) A laundry is often better as a half bathroom or incorporated into another room. As you build you need to see if the lot looks balanced and don't be afraid to change the plan as you go. I don't think anything I started to a plan ever stayed to the plan.

Thank you guys this is all very helpful. I don't want to mark this as solved yet, probably should have put it in a different forum. I like reading how other folks are doing things, and see what I can adapt to what I want to do.

Jo gives a good summary of how best to build a Lot, imo. Use doors, windows and major furniture items as reference points to judge how big a given space should or needs to be.

There are only two other important things I would add to the above suggestions.

Firstly, if the house you're trying to mimic has a defining feature or attraction, then do try to recreate this as much and accurately as possible, even at the expense of other aspects if need be, to a certain degree. This is important, since without this feature it would presumably be just another house.

Secondly, maintain proportion.
For example, there are countless houses uploaded where the kitchens are way too big in comparison to other rooms, especially living rooms. In almost all real-life houses, the living room is the biggest room in the house. And it should be, since it is there that most of the "living" takes place, with all other rooms being of a more limited utilitarian nature. Not just a place for a sofa and TV, the living room can often also include a corner with a computer desk (1-tile or 2-tile), an alcove with a piano, a small reading area with bookshelf and one or two chairs, and so on. It is the room wherein most everyday activities should take place. All other rooms are to some extent utilitarian, which serve more limited purposes.
I also see way too many houses with grotesquely oversized bathrooms, imo.

I thought that the grids when you're building is a 3' square. This matches SOME real proportions, but not all. Real halls are often 3" wide, but a 1-square-wide hall would be a problem for sims trying to pass each other. A double bed in the sims is 3 squares by 2, but that would be 9 feet long by 6 feet wide, and a REAL double bed is much smaller (6 by 4). Other things are closer: a sims closet is 6X1, a real one is 6X2. Sims counters, sinks, stove, frig are 1 square (3feet) - real ones are almost that big. (as are toilets, tubs, and chairs). So I generally use that "1 Sims Square = 3 feet of real space". I just make allowances for sims wanting more room to move - like bigger halls and bathrooms. A typical "powder room" - just a toilet and sink, is about 4X4feet, but that translates to a sims room of only 4 squares - too tight, but only because they like to party in the bathrooms...

I do a combination of all of the above Usually using the [1Tile=3Ft] standard.
For instance, in my RL house, the door frames and the stove and refridge are all about 3 feet wide - and they are 1T objects in the sims... but, you gotta take into consideration sim routing quirks and the basic logic of living. I find, when building from a plan, if you take the house's outer measurements and divide it by 3, you get a pretty good idea of what size property you'll need and where to place the house on it so you can add a driveway and other outdoor amenities/landscape as you want.
The most important aspect (IMHO) of building from a RL design is to get the outside "look" right. If the house looks the same from the outside, a lot of internal justifications can easily be overlooked.
Remember: Have FUN!

I just build. Make sure there are enough space for Sims to move around easily. Put in stuff that looks useful rather than pretty - and then I spend a day on the roof.

I go by the size of the window/door (or things like stoves and sinks). 1 window = 1 square. It doesn't always work out exactly, but I have made some pretty nice houses thanks to some very nice floor plans. Sometimes it doesn't work out perfectly, and sometimes you have to get rid of rooms (being that sims don't need to do laundry, so I usually turn the washing room into a small bathroom or just more counters if it's near the kitchen) plus sometimes you have to widen corridors or bathrooms to accommodate for sims stupidity.

I use the stove or the bed as a measure, and I tweak floor plans to sim needs. F'r instance, IRL you can shove a double bed up against the wall and it's still totally useable, but you can't do that in game. (Without a mod -- I am aware of the "Use Inaccessible Beds" hack, but when I am designing/adapting floor plans, I build as if it does not exist. And the original question was about how do you build/adapt, not how could you build/adapt.)

I've had the same problem in SIms that I've seen or had in real life; a pretty little house, OK for a couple. Then the babies start coming, and the kids want pets, and the kids are doubling up in bunk beds, and the baby is in the kitchen and there's not enough money to expand. I only wish it was as cheap to change and add rooms in real life!

I agree, I calculate 1 tile as 1x1 meter. (3 ft would equal 0.91 meter so, it's approximately the same)
For example I once measured the contessa Angie when she had passed out on the floor, and she was appr. 1.75 tiles.
In addition the Billy book case is appr 0.8 tiles wide. (IRL it's 80 cm)

For measurements, I just half them all. (i.e- 11x20 = 6x10)

Also, houseplans.com is a wonderful place for floor plans. You can just save the picture and start. (There are pay options, but those are for actual physical blueprints for contractors)

I've found two things extremely helpful:
1) Sketching things out on graph paper before building it in-game;
2) Sticking to designs that can easily be modified so it works in the Sim world versus our own.

And, strangely enough, I've never had a "bathroom party" in my game. Maybe I'm lucky.

A standard door frame is 6ft - and a normal door in TS2 is roughly 14 to 15 clicks high