I’ve used DAVID. Getting decent scans with it seems to be a bit of an art, and depends to a large extent on the hardware. A few things to keep in mind when buying equipment:
-The smaller the width of the laser line the better. Cheap DIY store laser line levels can work, but they generally have quite fat laser lines.
-The number of polygons in your model depends on the resolution that you film at (1 pixel gives 1 vertex, but a model typically takes up only a third of the camera’s field of view). For this reason you will likely not catch very small details when scanning a reasonably sized model.
-You want to have a camera that has good frame rates at the chosen resolution or a method to move the laser over the model very slowly. Affordable webcams currently don’t seem to offer both high resolution and good framerates. Many of the best scan examples on the DAVID website were done using a B/W CCD camera costing about $1000.
-Scanning is done in near darkness, so noise can be a problem. I think this is the number one killer of scans. It is therefore best to use a camera that has good in-software controls for exposure etc., or a CCD sensor.
-Native B/W cameras are best as every pixel is used. If using a red laser line with a colour camera (even in B/W mode), only 1 in 4 pixels is used, and using a green laser (more expensive) means 2 in 4 pixels are used.