Mapping of Physical Objects to Digital Computation:
It is important to understand and choose the appropriate mapping of physical objects with the possible feedback.

Mapping of objects include:

• Choice of the input object:
- Why a particular object is chosen as input modality?
- Is the relationship appropriate between chosen object, its actions & provided output?
  (e.g. using a metaphor of cricket bat & performing gestures of hitting a ball should result in a game of cricket, not football)

• Placement of the input object:
- Is the object used for input (control & manipulation) placed properly that user understands the next steps of interaction?

There are two ways to choose mapping of the object:
1. Abstract object:
The chosen input object may not have any kind of relationship with provided output; however, there may be a possibility of performed actions associated with provided output. Reactable project uses abstract objects (cube, triangle, hexagon etc.) to represent music.

2. Specific object:
The chosen object have a very clear relationship with the provided output, so that user is able to make direct relationship between input and output. Here, the actions associated may have or not have any kind of relationship with provided output.

E.g. Urban workbench project uses specific building elements & clocks to represent shadow, wind etc. in a newly designed architectural space.

Actions and its Association with Objects:
actions associated with the objects must provide immediate feedback for further steps of interactions. Here, actions supported by the objects must be based on well-understood actions related to the object.

E.g. if wine bottle is chosen as input, the opening of a bottle cork is a well-understood action
Appropriate coupling of tangible and intangible representation

Output of TUI can be represented both in tangible and intangible format. It is very essential to understand the balance and perceptual coupling of tangible representation to dynamic intangible representation. Tangible elements should be over shadowed or even should not be invisible.