How-to: Create animated visualisations in Stradview

Stradview is particularly focused on visualising data, especially surfaces contained in the data. It provides high quality surface and volume rendering, and both these and reslice-based visualisations have a variety of unusual features:

• The surfaces are particularly high quality. In most software, surfaces are about the same resolution as the underlying voxels, and frequently the voxel shapes can be seen as noise on these surfaces. In Stradview the surfaces have sub-voxel accuracy. Also, the surfaces are made up of a particularly regular set of triangles. Both these factors significantly improve the display of small features in the surfaces.
• Surface and volume renderings both handle shadowing and ambient and radiant light, to generate realistic visualisations
• Reslices through the data can be both in orthogonal and arbitrary orientations, and these are aligned to the surfaces in the 3D window again with sub-voxel accuracy.
• Reslices and volume renderings can easily be cropped to the created surfaces, which allows removal of unwanted data, as well as interesting combined displays of slightly transparent surfaces together with the data inside these surfaces.
• Stradview can handle large data sets and surfaces with very large numbers of triangles very efficiently, which means it is possible to analyse even very high resolution micro-CT data sets with a high degree of detail.
• Dynamic visualisation of surface intersections with all reslices, particularly in combination with accurate Cortical Bone Mapped surfaces, enables very easy assessment of the location of a surface.

All these visualisations are available in real time, but sometimes it is useful to record an animation in order to demonstrate a result more widely. The script task can be used to do this: specifically it can record a sequence of visualisation images which can easily be turned into a video using external software.

Crucial to this task is the ability to gradually change the orientation, location or zoom of a surface or reslice, so that images can be recorded at regular points as the visualisation is changed. The cursor keys enable this in all visualisation windows, with the rotational or translational increment set within the Mouse and keys configuration. A script can then be used to automate the various movements, and control which visualisation window is saved on each increment.

Saving a complete rotation of the 3D window, for instance, is performed with a very simple script. Much more complex animations involving multiple synchronised visualisations are also possible.