CERN Accelerating science

Visworkplan 20120223B

As is standard for Geant4 Planned Features documents,

(1) means expected to be done in first half of year

(2) means expected to be done in second half of year

(*) means may get to this in second half of year or may take longer

Qt: Show geometry hierarchy of touchables including buttons to control visibility - (1)

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gMocrenFile: Add support for rendering patient from 3D parameterization - (1)

Currently only supports nested and phantom parameterizations.

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gMocrenFile: Add an extended example to show how to use gMocrenFile with scorers - (1)

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New driver to produce image files in batch - (1/2)

Support (a) window-less mode but still requiring graphics card and (b) graphics-card-free mode.

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OpenInventor: Extend SoXtViewer - (1/2)

New functionality such as save and restore viewpoint and save and replay fly-through (originally motivated by beam line applications).

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Integrate Inventor viewers within the QtUI environment - (1/2)

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Numerous small on-going improvements to rendering speed, interactivity, robustness - (1/2)

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Key tasks for which we do not have manpower:

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Investigate dynamic loading of visualization drivers - (*)

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Change from current flat format to hierarchical format in VRML - (*)

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Integrated visualization of field lines - (*)

Electric, magnetic, maybe even gravitational.

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Full support for visualization of boolean shapes - (*)

Boolean operations on polyhedral representations of Geant4 solids for visualisations were improved in 9.3. But it is still not a general solution. It is a workaround based on finding a good way of shifting one solid relative to the other by a small amount. The most serious computational problems arise when faces coincide. We have had a simple shifting algorithm in place for many years; in 9.3 this algorithm became a little more sophisticated. In a test it fixed 96% of failures. There remains a stubborn 4%. (The effect of a failure is to prevent visualisation of the boolean solid, except with the ray tracer driver, which does not rely on polyhedrons.) We might be able to make the shifting workaround yet more sophisticated but, ideally, we really need a comprehensive solution, a daunting re-write and improvement of the basic facet-intersection algorithms.