Volume Rendering and Loadable Modules: (Engineering & Usability Notes)

Volume Rendering

Slicer 3.4 Release Priorities

• Fixing the progress bar
• Software rendering is slower now that it was in previous version. Need to make sure that performance is optimized for release.

Additional issues

• When a render method is selected, a request render event needs to be triggered so viewer is updated
• Render options should switch on the selected renderer so that inapplicable options are hidden, and only relevant ones are exposed.
• In the 'Help' panel, would be nice to describe each render method so that they are demystified
• In 'Details' panel, when switching to a new tab, need to keep scrollbar position in the tab being exited, so same view is displayed next time user returns to that tab.
• In 'Threshold Tab' the widgets could communicate the options better. Currently, the threshold menubutton's options (ramp, rectangle, none) set up an expectation that reverting to the 'none' option after applying ramp or rectangle, will remove the thresholding operation. To communicate the underlying functionality more accurately, maybe simplest fix is to just remove the 'none' radiobutton from the menu, and select either 'ramp' or 'rectangle' as the menubutton's default value. Then, as soon as a user adjusts the range widgets below, the threshold is applied. If they wish to revert, they can select Slicer's "undo" (if the operation is undoable).
• Can we save parameter sets?

Some additional thoughts

• The GUI's vocabulary is appropriate for developers, and less so for users of this rendering functionality. Suggestions for making it more user friendly:
  • rename 'Details' panel to 'Volume Rendering Options'
  • rename 'Performance' tab to 'Method'
  • nix the 'Performance/Quality box entirely. Expose Rendering Method selector at the top of the tab, making it the main point, and switch display of other options based on what's selected.
  • use a vtkSlicerPopUpHelpWidget to explain the options and speed/quality tradeoffs for each rendering method.
• When no data is loaded, the 'Details' tab is unpopulated. This can be confusing to a newbie user. At least a text widget could be displayed there saying that a volume must be loaded for volume rendering options to become available...