Special considerations apply when selecting the photo image to use with Camera Match tools and commands.
● It is best to start with a photo image that is the same size and resolution as desired for the final composite image.
● When taking photos of a site, do not use special lenses that straighten perspective views or distort the image. Such lenses create images that are impossible to match.
● Avoid taking photos head on, where the camera is pointing perfectly straight down the center of a corridor, or exactly perpendicular to the face of a building. When setting up control lines in Camera Match, if a pair of control lines become extremely close to parallel, the calculated view may be prone to errors. Similarly, when a vanishing point is extremely near center of the photo (when taken), the calculated view may have errors. If you require a photo like this, take several photos from slightly varying angles. This will provide some back up options if your first choice has difficulty.
● Include the scope of project when you take the photo. All of the proposed parts of the model that you wish to show should fit within the photo. This may seem obvious, but it is easy to overlook when you are on site with only the existing conditions.
● Most lenses create some degree of barrel distortion in their images. This lens distortion causes straight lines (or edges) in the photo to look curved, providing less accurate results. This lens distortion should be corrected, on an uncropped and unaltered version of the image file. Some popular image editing applications have tools for this, but there are also some low cost applications that are designed specifically for this purpose, such as PTLens.
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