3rd pug 98 1) Haptic Rendering of Volumetric Soft-Bodies Objects ----------------------------- Matt 2) Volume Rendering with Haptic Interaction: - Currently GHOST SDK (1.2?) represents environment as collection of geometric objects. APSIL, Ghost Application Programming Supplement Interface Library will allow volume visualization based on voxel representation. Material properties such as friction and stiffness may also be defined. - Volume rendering based on volumetric objects useful (questionable) when user attempts to: - precisely locate a feature within a volume - fly inside a volumetric object - understand the spatial arrangement of complex 3d structure - tactilely operate on an object Yes, this is relevant for our purpose. We might wish to explore using volume visualization based on voxel representation. --------------------------- 3)Haptic Rendering... Surgical Planning 4) Rendering of tool-tissue interactions 5) Assessment and Validation ... Surgical Simulator 6) Soil Simulation 7) Nearest Neighbor Collision detection 8) Adding Haptic device to VR UIs 9) Tactile Max --------------------------- Andrew 10) Implementation Issues in Adding Force Feedback to the X Desktop: This paper describes implementation issues encountered in a project to add force feedback to the X Window System. Issues they encountered: intercepting haptic motions and translating them into mouse commands. For example, clicking on a window to make it pop-up, would require the system to translate the haptic motion (pressing the window menu) into a click of the mouse. Other issues involve the haptics server and it's interaction with X; GHOST creating false boundaries due to its implementation of friction; PHANToM 1.0's re-orientation to mimic the positioning of a mouse. Another issue is that debugging the system proves to be very complicated, since they are working with real-time systems such as the haptic arm and forcefeed back. Their GUI uses dimples, ridges, negative viscosity, pressure sensitivity, force feedback and buttonlike clicks. The only thing they concluded about this, was that the use of dimples in drag-and-drop operations, "seem to make a noticeable improvement in interction speed", while the use of dimples in menu items "has a noticable negative effect." --------------------------- Gary 13) Network Access to a PHANToM Through VRPN The Virtual Reality Peripheral Network (VRPN) is a library used to provide network- and manufacturer-independent access to VR devices (such as motion trackers, mice, and haptic devices) from VR applications. Using VRPN, applications can be written without regard for the pecularities of individual devices or their location on the network. This greatly simplifies the development of VR apps and allows maximum utilization of existing equipment. - The library is class-based, allowing easy extensibility and access to device-specific information when needed. - Haptic devices are split into virtual input and output devices to separate their various functions. - VRPN and GHOST are incompatible. Thus, programs would need to choose which toolkit they should be developed for. This can be a useful toolkit for our programs, especially if we obtain more haptic or tracking devices in the future. It should be investigated further for its advantages and disadvantages. --------------------------- James 14) Acoustic Cues for Haptic Rendering Systems - Using sound to compliment and enhance the level of emersion when interacting with a virtual environment. This is particularly important for onlookers who are not themselves interacting with the haptic device/virtual environment. - Midi: pre-rendered sound samples stored in the memory of the sound card. Therefore, sounds created through MIDI demand little CPU. - This article discusses sound envelopes for different materials and the relationship between contact velocity and the subsequent sound generated. - Sound Textures: Texturing a surface to play different sounds at different points on its surface. Giving a more realistic/less redundant sense of the object's true properties. --------------------------- Sara 11) Assembly Simulation They integrate the Phantom w/ their mechanical CAD program, DATum, which uses both CSG and B-reps. Touch: 3 cases 1)last pt checked was outside model: intersect vector from it to current pt w/ all faces 2)last pt checked was inside model: find min distance to boundary & compare to movement vector? 3)prev pt on the surface: check movement direction vs min distance points to adjacent faces Plus sidedness tests if surface (vs. volumetric) model Move: Translate object w/ movement of Phantom, taking into account friction or weight of object. Collision detection: They build on OBBTrees, V-collide (I-collide was '95; V-collide is '97 successor), & PhD work of P.Hubbard at Brown (yes, he does use sphere-trees). Start with Oriented Bounding Box trees, then faceted approximations to objects, finally curved surfaces. How do they do all this at 1000Hz? They don't say. Assembly: Builds on Touch, Move, Collision Detection. Only have very simple objects. =========================================================== Young 12) Springs & Constraints for 3D Drawing In this paper , they present examples of haptic sculpting using springs and constraints for 3D drawing. They introduces two application : "Dynasculpt and GridDraw" Dynasculpt allows 3D sculpting by attaching a sprung virtual mass to the Phantom position and creating a ribbon or tube along the path taken by the mass through space. A linear and damped spring is used to attach the mass to the finger position.and the spring is also used to give force feedback to the user. Damped spring helps make smooth trajectory. And Griddraw is used for constrained 3D drawing . A typical problem encountered in 3D sculpting applications is effectively navigating 3D space.. Griddraw define haptical force grid and helps user draw straight line along axis quite easily. =========================================================== 15) SCIRun ... for Sci Viz 16) Haptically enhanced molecular modeling 17) Incorporating Haptics into mining 18) Role of Haptics in shared VEs 19) Project... Human motor system 20) Impaired person's use of phantom... =========================================================== Cheston 21) Psychophysical experiments in a complex virtual environment This NIH project has two PHANToMs and a HMD, carefully calibrated to produce a workspace (30cm X 40cm X 40cm) with a calibration error below 1mm on average. They don't mention how this "careful calibration" was done, however. The setup was used to conduct several psychophysical experiments. The conclusion arrived at, was that the setup was similar enough to the physical world so that experiments done on it produced the same results as those conducted in the physical world. CONCLUSION: NOT RELEVANT