This setup is a pretty simple example of how a molecule electropotential field can be explored using a multi-modal display. The visual rendering provide a general overview using iso-surfaces at zero potential and at a positive and a negative potential. Volume Rendering is also added to show the electropotential throughout the volume.
Two different haptic modes are appropriate for effective haptic rendering of this kind of data: the Vector Follow Mode and the Vector Front Shape Mode. These vector modes are applied to the gradient of the scalar field. The follow mode thus convey the orientation of the gradient and guides the user to follow the highest gradient direction path between high and low potential. The front shape mode, on the other hand, renders a haptic iso-surface at every position in the field.
The SHARC aircraft is an experimental unmanned aerial vehicle (UAV). In this example the air flow from a computational fluid dynamics simulation (CFD) is explored using multi-modal interaction. While only simple properties can be rendered visually without cluttering the display, interactive stream tubes and haptic feedback can be used to freely explore the full 3D volume.
Two different haptic modes have been showed to work well with this kind of data: the Vector Follow Mode and the Vector Vortex Mode. The follow mode convey the flow orientation and its strength. The vortex mode, on the other hand, produce a haptic guidance surface where the vorticity of the vector field is strong. This plane guides the haptic instrument so that it is easy to find and follow vortices and areas of strong turning winds.
Modern MRI-scanners are capable of aquiring animated blood-flow data from withing a beating human heart. The phase contrast pulse sequence used to acquire flow information produces poor tissue contrast when used to scan full 3D data, so the visual quality of the dataset is low. Both the poor tissue contrast of this kind of data and the fact that the noisiness of MRI data makes automatic extraction of features difficult makes it an interesting target for multi-modal methods.
The task of exploring this kind of data is effectively guided using the Vector Follow Mode, applied to the blood-flow data. The follow mode provides guidance and information about the local flow. The characteristics of flow can easily be recognized and also be distinguished from noise, which shows the effectiveness of human perception. By also adding the Vector Force Mode that pushes the haptic probe in the direction of the flow, an extra channel of information about the anatomy of the heart is provided.
The Scalar Gradient Mode can also be applied to the flow magnitude. This produces a push towards high flow which makes it easier to find main blood flows and follow the major streams. However, the pushing effect also obfuscates detailed information from the other modes, which makes it unsuitable for close examination of the identified flow.
