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‘Pop-up 3D’ with Flash

One of the simplest 3D modelling techniques that can be used with the Flash is something I call ‘Pop-up 3D’ – as it works in a very similar way to old children’s pop-up story books. The structure that you want to give a 3D appearance to is distributed across a number of layers – with the top layers having the parts of the structure that would be closest to the viewer.

Bathymetry round the Stirling Castle site

In the final movie the layers are moved according to your mouse position, with the top layers moving with the mouse, and the bottom layers moving away. If you place your mouse cursor to the top right of the movie, therefore, the top layer will be displaced to the maximum extent in this direction, while the bottom layer is displaced to the maximum extent towards the bottom left corner of the movie frame. Intermediate layers move proportionately smaller distances in the appropriate direction – it is quite a lot of fun setting the scaling of the movement to give a believable 3D effect.

This technique gives allows a model to be viewed from a limited range of viewing angles, and works best where this would be a ‘natural’ situation. One example is for maps – and the model displayed here is an early draft of a contour map showing sediment errosion from around the Stirling Castle, a shipwreck dating from 1703. Each contour height has been separated onto a new layer, clearly demonstrating the technique.

In the final version, which can be seen on the RASSE project website, the contour areas have been replaced with a multibeam image of the seabed, which gives the model a startlingly realistic 3D effect. In the final version I have also added data from all three survey years, showing how sediment is currently being deposited around the wreck site.

RASSE website, final 3D model