You can design your own house if you have the desire to do so given that not everyone would be willing to spend time on such a thing which is often better left upon professionals to take care of for you. The thing however is that leaving entirely upon professional companies would not always result in something that you would be entirely satisfied with given that you may have your own ideas in terms of how you would like your property to look like.
Unless you can find courteous and helpful architects who are willing to spend countless numbers of hours working with you to come up with the best possible design for your new property, it may perhaps be a good idea to learn some of the things yourself and try to come up with your own design for your own house. All you would need is usually a sketch to be able to design your own house.
And since the use of modern technology has become popular in designing houses, you will be able to benefit a great deal from a 3D visualization software. This will allow you to get a 3D render of the area that you would like to develop so that you can take appropriate measurements and try to come up with a new and better design without compromising on anything.
If you use a 3D visualization software then everything that you do would be as accurate as it could get as opposed to doing it manually as manual sketches are usually prone to errors since they are usually two-dimensional.