AThere are times in life when surprises are wonderful. "It's a girl!" would be one of those times. "The winning number is... yours!" is another. But when you're planning a house renovation, you really try to keep your surprises to a minimum.

Although you're probably never going to get a precise picture in your mind of what a new space will look like until it's built, there are things you can do the help you visualize the end result.

Building plans are an abstraction and can be hard for non-architects to understand. You could ask your architect to draw a freehand sketch that will convey the look of the space in less abstract terms. If your architect is willing (or you're willing to pay), he or she can build a scaled-down model to get a better sense of the overall size of an addition or the volume of an interior space. Many designers work on computers and can generate drawings that show a virtual snapshot of the space. Most of these 3-D modeling programs will allow you to "walk" through the space, can accurately imitate materials (brick, stone, wood, ect.) and can even show the way the light will feel in the room at a given time of day.

But if you're not working with someone who has these capabilities, or don't want the extra expense to generate models like this, there are still things that you can do by yourself.

First, get a tape measure and carry it around with you for a few days. With the dimensions of your proposed space in mind you can measure out rooms that are similarly proportioned. If you're not settled on the size yet but see a room that feels good to you, take out your tape and measure its length, width, and height.

Another handy tool is masking tape. It will be easier to "see" new partitions, windows, or cabinets in a house if you tape them out on the floor or walls ahead of time. This is very helpful when you're trying to imagine the size of a new kitchen island in a room. Also, if you're trying to picture how big an addition will be from the exterior, get some bamboo stakes and string and measure the space on the ground outside your house.

Finally, a trick that interior designers use to assemble colors and materials is to make a finish board for each room. As you're picking colors, materials, and fabrics for your space, get a sample of each and affix it to a piece of presentation board. Be careful to use the approximate relative amounts of each material as it will appear in the room i.e. get a larger piece of flooring than a backsplash accent tile because there will be more of it in the room.

With a little imagination and a few simple tools, you can do a lot to visualize how a finished space will look.