ImageModeler 2009

Written by Martyn Day

Published Fri 24 Apr 2009

While it is said that a picture can paint a thousand words, it seems a picture combined with Autodesk Image-Modeler can paint a rather more impressive 3D model. Using a collection of digital photographs, or scanned images, the software enables the construction of buildings, scenes or cities into accurate, textured 3D models which can be imported into CAD or visualisation systems.
 

3D textured interiors can also be created from photographs with ImageModeler

ImageModeler is intended for architects as well as 3D artists from the games, film and TV industries, and can be used in urban modelling, interior modelling, games production, surveys and as an alternative to laser photogrammetry.  

ImageModeler’s interface is very similar to Stitcher Unlimited, the software that seamlessly stitches images together with hardly any human interaction. It’s clear on loading ImageModeler that it shares the same development and ‘no-fuss’ ease-of-use methodology. The interface consists of just seven buttons and a large grey workspace. That is, until you drop in some photographs with which to make a 3D model. A function bar then appears which steps through the workflow relating to the different views of the 3D space.
 

ImageModeler generates a 3D workspace from any number of static photographs. Therefore, buildings such as this museum in Salzburg, Austria, can be faithfully recreated using simple processes and modelled for a digital city project

Camera skills

There are four key steps: loading the images, calibration, modelling and texturing. It’s important when photographing the original images that you keep the camera zoom settings the same for each view. Fortunately, the software is pretty clever as this was my first error and it alerted me on my first import. However, it can work with images with different focal lengths. In fact, the developer encourages photographs to be taken from as many different angles as possible to enhance the conversion process.      

Work on a grand scale

Calibration can be carried out with any number of pictures, by matching points between the various views. The software supports rectilinear, panoramic (including 360 degrees) and aerial images – and even a mix of all three. As the software can work on a slew of images, it’s possible to work on a grand scale, modelling whole streets or squares in one go. The user moves from image to image referencing the same places in different views. As this progresses, the software automatically starts to project the 2D photos into a 3D space. To assist calibration users enter known distances, right angles and areas of coplanarity to improve the end result. 

As photographs are the source of the modelling process, the images of all the facades can be used to bring the model to life. The low polygon count is countered by the texture map detail on the building

It’s important to select points outside of the building being modelled, foregrounds and backgrounds. A minimum of eight points are required and once the system has enough points to calibrate the scene, a ‘tick’ dialogue appears.  

Once calibrated, measurement is possible from the image. A measuring toolset can be used to calculate real world distances from the photograph. According to Autodesk, if you’re using high resolution images it’s possible to get measurements within 1 per cent accuracy.  

Modelling in ImageModeler is carried out by drawing 3D primitives on top of the calibrated 2D image. There are snaps and constraints available to help align and adjust the 3D primitives and the software is optimised to generate polygon models of traditional architectural shapes. It’s also possible to import 3D models and textures. 

As ImageModeler works with photographs, the texturing is photorealistic. The software extracts texture maps from the photographs in a number of projections (planar, cylindrical, spherical or cubical). Autodesk has enabled a high degree of compatibility with Adobe’s Photoshop for image retouching. Textures can even be derived from a number of photographs and blended into one texture map. 3D meshes can also be texture mapped with UV mapping. 

ImageModeler 2009 features improved support for DWG, FBX for 3DS Max and MotionBuilder, as well as .MA for Maya. Both PC and OSX (Mac) versions are available. 

With ImageModeler, the user can create surprisingly complex-looking models that can be used for a number of visualisation purposes. Here, external facades are complemented by 3D scenes and imagery of internal features, alcoves and passageways

Conclusion

ImageModeler 2009 is very similar to Stitcher Unlimited in its methodology but as the end product is a lot more complex, a fair amount of interaction is required. There is a high degree of trigonometry going on as the user places calibration points and sometimes the results aren’t quite what was intended. Like most things in life, ImageModeler has a learning curve, yet in the hands of an experienced user the results can be breathtaking.  

Product: ImageModeler 2009
Supplier: Autodesk
Price: €1,077.23
www.autodesk.com/imagemodeler