Ever wondered how some 3D models look so life-like? Image based modelling and rendering (IMBR) is a technique that creates a 3D polygonal model from a set of 2D photographs. This technique can provide a fast and efficient approach to the re-creation of 3D objects, such as for instance, a historical building.

Entrée de la Chatreuse de Villeneuve-les-Avignon. Jiakun LI
IMBR has helped scientists across the world collect quantitate research data on historical architecture and biology. IMBR enables scientists to re-create complex geometric representations of objects, ones which provide scientists with a greater and more in-depth analysis of structure and form.
There are many 3D software applications that provide IMBR features such as ImageModeler, Maya, Blender and ZBrush. Although, these applications have a steep learning curve and price for users who are new to the concept and principles of 3D modelling and rendering. Luckily, there’s a free, opensource alternative: insight3d an opensource image based modelling tool.

Insight3d simplifies the process of creating image based models. All you need to give it is a series of photographs (taken from following a set of guidelines outlined in the user guide PDF) of a real building or scene and it automagically matches them and calculates the positions in 3D space, creating a 3D point cloud of the scene. All you have left to do is to use the inbuilt modelling and texturing tools to finish the model off.
Insight3d is available on Windows as a MSI installer or a standalone archive on Linux (which you have to compile yourself). If you have Windows or Linux give it a try, and read the tutorial which should gently guide you through the process of creating your own.
Here’s a quick one I made earlier…

The 3D Point cloud.

Triangulated user vertices with user drawn polygons.

The model in the overview mode. The cones represent the camera(s) in 3D space that took the photo.
