ImageModeler is a program for extracting textured 3D models from two or more conventional 2D photographs of an object, using the principles of photogrammetry to calculate structure from the positional differences of the same points in different images. The subject can be practically anything, from a small object such as an engineering component or domestic ornament, up to large objects such as vehicles, buildings or whole landscapes.
ImageModeler creates a 3D mesh of the object or scene, then uses the photographic appearance to create a texture that’s applied to its surface. The result is quicker and easier than creating a 3D model from scratch, though if you need a high level of accuracy for component breakdown, technical drawing or architecture it takes a lot of work. Photographic textures look far more realistic than synthetic textures, but you’re stuck with the shadows and reflections of the original photographs.
Available with single-user and server licences for Windows NT 4, Windows 2000 and Irix, ImageModeler can be used for building 3D versions of real-world objects or scenes for Web sites, games, simulators and movies.
It’s more sophisticated than Adobe Canoma, where you pin photographic objects to a fixed range of pre-set shapes. With ImageModeler, the shapes are extracted from the photographs, though you can speed things up by starting with the small set of shape primitives supplied. ImageModeler only extracts polygons, whereas the new Eos Systems PhotoModeler Pro 4 offers splines for true curves.
New features in ImageModeler 2.0 include automatic point placement, texture blending from multiple originals, an improved user interface and more export file formats.
The principle of ImageModeler is that you load and display several photographs of the same object, taken from different angles but preferably with the same camera/lens combination. Then you manually identify points that appear on all the images. These appear in a hierarchical list on screen as ‘helpers’.
When you have perhaps 20 or 30 points identified, ImageModeler uses these to calibrate the lens and camera positions. Then you can add more points to individual images, and the program will automatically position them fairly accurately where they’re visible in one or more others. You can fine-tune the auto positions. When you have about 100 points defined, you can try to extract the underlying geometry. ImageModeler can define invisible back faces by joining points, or ‘cull’ them to leave a hollow shape. Once defined, you can display the model in various levels of wireframe and shading up to a fully textured surface based on the blended photographs.
Models and scenes can be rotated in space to give better visualization angles. In wireframe mode ImageModeler identifies inconsistent or incomplete vertices by flashing them in red as you run the cursor over them – you can fix these with tools provided, though it’s fiddly for complex shapes.
Using ImageModeler is fairly easy – the controls are intuitive and the tutorial is good, though limited to a single subject. Placing a hundred or more points can be tedious, but the auto-positioning tool helps. Achieving accurate models takes practice, time and patience, but the results are rewarding.
The photographic stage is important too. While not essential, you’ll get the best results by shooting images specially for ImageModeler. Unlike earlier photogrammetry software, ImageModeler doesn’t require you to enter the precise details of camera positions and fields of view – its calibration process works this out.
Output choices include most of the popular formats for 3D modelling and rendering: OBJ, VRML. STL, DXF, Maya 2.0, Softimage 3D 3.8, 3D Studio Max, LightWave. It also outputs files for RealViz’s MatchMover camera tracking software.
ImageModeler is a good introduction to the principles of extracting 3D models from photographs: it’s easy to understand, the user interface is fine, and its accuracy is only limited by your originals and your patience. However, at this price you’d need a serious, professional interest in modelling.