1. StepCore.

* implement compile flags:
  - STEPCORE_WITH_QT
  - STEPCORE_WITH_ERRORS
  - STEPCORE_WITH_NAMEPROP
  - STEPCORE_WITH_GUIPROPS
* unit tests
* movement restrictions (IN PROGRESS)
* rigid bodies (DONE)
* collision detection with friction (IN PROGRESS)
* custom properties for bodies, make charge custom property (?)
* adaptive timestep solvers (DONE)
* correctly handle stiff ODE
* separate position and coordinate (PARTLY DONE)
  (for independent tolerance settings, symplectic solvers)
* global error estimation (requires jacobian ?) (DONE)
* multistep solvers
* symplectic and other nice solvers
* implicit solvers (!)
* more collision and constraints solvers
* NullCollisionSolver and NullConstraintsSolver
* molecular dynamics (potentials etc.) (DONE)
* massive springs (DONE)
* soft bodies (DONE)
* fluid and gas simulation (DONE)
* create common class for connectiong something to rigid body
* think about 3d

More TODO items for StepCore can be found in
Doxygen-generated documentation and in the source
code (marked as TODO or XXX).

2. Step.
* SVG theming
* do calculations in separate thread (DONE)
* use statusbar or small graphicsitem to notify
  user when creating items (DONE)
* saving animation (navigation through time)
* units for all quantitis, units conversion (DONE)
* user-editable notes (DONE)
* formulas in notes (DONE)
* custom scene background (PARTLY DONE)
* nice-looking descriptions for all bodies and parameters
  (with references to wikipedia or wikibooks ?) (DONE)
* configurable simulation-time controllers (DONE)
* configurable plots and summaries (DONE)
* KHotNewStuff for sharing experiments (Downloading: DONE)
* Tutorials (series of experiments with explanations)
* define multiple coordinate system and provide an ability
  to translate vector coordinates between them
* viewer (locked) mode: allow to change only
  explicitly selected properties of the experiment
* grid and snapping
* "fixing" a tool for creating several similar objects
* Object Information (Help Widget)
  Subject: Semantics

  While the code is probably valid xhtml, I can't help to notice you might
  want to use the "dl","dd" and "dt" tags instead of just a regular "li"
  embedding a semantically worthless b tag.

  http://www.w3schools.com/tags/tag_dl.asp for more info and an example.
  Next to being more semantically correct, it allows you to style the pages
  better and easier for different kinds of viewing devices since you can
  then select both elements of the definition separately.

More TODO items for Step can be found in the source code
(marked as TODO or XXX).

3. Future ideas

* Create a game based on Step. Original idea by Jason Harris:
On each level, you were given a goal and a list of equipment that 
you could use to build a machine to achieve the goal.  The equipment could 
include lots of different stuff: balls of various types (tennis, bowling, 
baseball), springs, trampolines, guns, ropes, pulleys, belts, gears, conveyor 
belts, cats, mice, light bulbs, elecric fans, model rockets, TNT, etc.  You 
would place all this stuff on the playing field, press "Go", and see if the 
level's goal was achieved by your machine.  If not, you would modify the 
machine and try again.  It was a lot of fun for a young proto-physicist :)