This is a great question with a couple of answer versions - short and long!Short
- you could try what you suggest and sketch out on paper and then try with cardboard - I have done this before with some of the more straight forward projects I've created and it works, although I have often had to make more than one version of my sketch to get to my end point.Long
- if you want a true "to scale" style replica of something that has more intricacy and detail it takes a little bit more effort. e.g. I am slowly working on a replica of Tara (from Gone with the Wind – movie version) which only has a façade since it was a movie set, and then I need to “create” the other sides.
I start by finding photographs of each aspect of the building/object I want to design and get a good feel of exactly how each side plus the roofing relates to be sure I can make a stable replica, or if I will need to take some creative license and modify something to be more sturdy. Once I'm sure that I can build it without deviating from the plan, I pick the most important aspect of the house (usually the front) and begin "drawing" each side using an image projection tool.
You can use either a KopyKake, which I don't have and can be quite pricey, or a smart phone application. On my iPhone/iPad I use Camera-Lucida, or through the Google Play store there's an app called Artist's Eye Free (all credit to another member here – GingerArt
, she pointed these tips out to me a couple of years ago when I wanted to make my own template). Another technique I have used once is to create a photocopy of the façade I want to start with, and then use the enlarge feature on the copier to scale up the image, then your photocopy becomes your first template from which you just need to cut around the edges and cut out windows and doors. With this method you are limited to the size of paper the copier will handle, and it can be fiddly finding the right percentage scale-up, as most people would be using a copier away from home where all your baking reference implements are
Going back to the smart phone apps - the app can be used to "project" a version of the image onto a surface to enable you to trace it exactly, and help you place windows and doors simply and accurately. This projection can also be enlarged and shrunk to make the image whatever size you want, allowing you to immediately choose the size of your masterpiece (I like to have my largest baking tray on hand when I do this to make sure that none of my pieces is inadvertently larger than I can fit on the tray!)
Once you have completed the first side, measure the height of the wall from the first piece and draw your wall height for the second piece to the same size, and then adjust your projection for the second side of the building so that you have the heights equal. Sometimes I find that the side and rear pics of houses are taken on an angle or are incomplete and using the “projection” method is impossible, at this point, once I have established the front façade, I have established the relative sizes of the rest of the template and then I can immediately “sketch” out the wall sizes, and then estimate the placement of the doors and windows (you can do size measurements and ratio downsizing if you’re a keen-bean, but unless someone is going to get out a micrometer and measure your creation, after the front side is done, the rest can quite often be done ad-lib and no-one can tell that you’ve free-handed the location of windows etc
The creation of the roof is usually the hardest part; you need to take into consideration not only the width (which can easily be measured from the length of your wall pieces) but also the height, (depending on pitch of the roof), and any roof adornments/modifications such as gables or turrets. These can get very fiddly and will take even longer to explain! At that point I suggest that you erect the walls and reverse-engineer another turret or gable from another pattern to fit with the design you want.
One thing about templates, I am a “I might want to use it again” kinda gal, so instead of making my templates out of cardboard, I go to the dollar store and buy cheap plastic children’s placemats (the kind that sound like a wobble board if you wobble them). It usually costs me $2 for 4 mats, which is often enough for more than one template. I copy the paper template on to the plastic mat, cut it out with an X-acto knife, label each piece with useful info about how many to cut and where it should be placed and then I have a nice washable, re-usable template that can be employed another time, not to mention, the rigidity keeps the template in place on my gingerbread much better than I find with my cardboard. I then store all my templates in plastic sleeves in a very fat folder in my bookshelf
I hope this helps, don't hesitate to ask any questions or PM me if some of this doesn't make sense.