Usability and performance requirements

Usability requirements

As we are using emerging technology it is especially important to consider the usability of the application because users are likely to not have used something similar before. This is mainly the case for the HoloLens application, although the webapp will be partnered with it, which may affect familiarity.

HoloLens usability requirements

In the context of the HoloLens we will define a simple interaction to be any interaction that consists of maximum 4 actions from the following list:

• Focusing Gaze
• Selecting Menu Item
• Performing Manipulation

A complex interaction may be made up of greater than 4 actions and primarily deals with changing between view context. The two view contexts are Standard view and Expanded view. Standard view is considered to be the base state a model loads in, while Expanded view is when all meshes are spread out and separately interactible. Only models are expected to have an Expanded view as described here.

Interactions that are required to be simple:

• Loading a model or DICOM (allowing for browsing through available options)
• Unloading a model or DICOM
• Rotating, Scaling or Expanding a model
• Scrolling Through or Scaling a DICOM
• Rotating or Changing Transparency of a model's mesh when it is in Expanded view

Interactions that may be complex:

• Log-in process
• Accessing a manipulation only available in Standard view from Expanded view
• Accessing a manipulation only available in Expanded view from Standard view
• Adding a Data Marker to a mesh of a model

Webapp usability requirements

The requirements are simpler for the webapp, as the realm of interaction is more mature. The requirements for the website are as follows:

• A User should be able to filter out models and DICOMs not uploaded by them or vice versa
• A User should be able to perform model uploads without knowledge of what is going on behind the scenes
• A User should be able to change to a different section of the webapp through a menu with no more than 4 clicks

Performance requirements

From the two platforms which are chiefly being used in the user facing solution we can draw up a number of basic performance requirements to improve the experience of the user.

For the HoloLens:

• Loading a model from storage should take no more than 5 seconds
• Loading a DICOM from storage should take no more than 5 seconds
• Framerate for displaying models should aim to not drop lower than 30 fps
• Preprocessing should be done by the webapp backend to increase mesh performance

For the Webapp:

• Data loaded by default should be limited to decrease load time so that most requests are not longer than 2 seconds