How to Create a Virtual Tour
This guide is an overview of the basic principles of how to create a virtual tour. While not delving deeply into any one particular aspect of virtual tour production this guide should help you understand the steps you should be thinking about when virtual tours approaching virtual tours and panoramic photography in general.
They say a bad workman blames his tools and this might be true but even the world’s best blacksmith can’t make Excalibur from a tuning fork and an old tea bag. While it is possible to create panoramas with a camera phone and a nifty lens you get off bobsrubbishlenses.com for £3.99, your panoramas are going to be the virtual tour equivalent of a cave painting. For any budding panorama or virtual tour enthusiast I recommend at the very minimum investing in a high quality DSLR camera and a wide angle lens (preferably fisheye). With these two pieces of equipment you can start to create some half decent panoramas to use in your virtual tour. If you are looking to go professional or take HDR images I heavily recommend investing in a ball head tripod and decent Panohead as well.
Preparing the Scene
Creating a good virtual tour scene is as much about what your filming as it is getting the technique right. Take some time to think about what you are trying to achieve from the scene, for example if you are filming a dynamic outdoor scene you should think about how the weather, season and time of day will affect the shoot. If you are shooting a kitchen for a real estate agent then you might think about laying the table or lighting candles to create an atmosphere. Remember that at the end of the day a virtual tour is a series of artistic photos. Approach the scene like an artist and you will produce something special (eventually), approach the scene like a surveyor and you will end up with the virtual tour equivalent of a fiat punto, functional but you’re probably not going to turn any heads.
The Nodal Point
To produce a panoramic scene you must take a complete sphere of images from one individual perspective. This perspective is called the nodal point and is incredibly important when shooting a panorama: if your nodal point is even a few millimetres off then the perspective shift that occurs between images will make them impossible to stitch together properly. If you have a tripod and Panohead you can set the Panohead to keep the exact nodal point for your camera. If you do not have access to this equipment then you can use a number of methods to keep your camera on the nodal point. I highly recommend the Philopod Pitch Variation method, a description of which you can find online.
Taking the images
The type of lens you are using will dictate how many images you need to take. For example using a standard lens you will need to take between 12 and 16 images for one level of a cylindrical panorama in landscape mode, whereas a fisheye lens can craft a 180 x 360 degree panorama from six shots alone. For this reason we recommend investing in a quality fisheye or wide angle lens. Once you have chosen your lens and have secured your nodal point either through use of a tripod or pitch variation method you can start taking your images. Whichever method you use you want to make sure there is between 30% and 50% overlap to your images, this will help you stitch them together seamlessly in post processing.
Creating a virtual tour and stitching together images into a panorama are two very different processes requiring separate software. I highly recommend both PTGui and Autopano as fantastic stitching choices, both are available for trial download. Depending on what software you are using you can now simply drop your images into the stitching program, use the mask function to block out any equipment that has accidentally turned up in shot, then allow the program to stitch the panorama for you. If your images are around centred around the nodal point and have sufficient overlap your software should have little problem matching them into one panorama. You can now export this panorama in JPEG or tiff format as a scene for your Virtual tour.
I won’t go too far into post processing as there are hundreds of tutorials online for how to doctor your images and this will vary hugely on what effect you want to create and whether you have used HDR or not. I will say that if you do post process (and you should even if it is just to up the contrast) then keep your images as high quality tiff files all the way up to building your tour, that will keep you from losing any image quality. Once you have finished your post processing you may need to reduce your image size for use with the web, I recommend using Photoshop or GIMP to resize the images into JPEGs of between 0.75 and 2.5 megs (and not more that 5000 pixels wide) depending on whether you value quality over quick loading times.