3D Visualizer with Oculus and Hydraokreylos2026-09-23 | 3D Visualizer with Oculus and HydraVruis User Interface on Valve Index Headsetsokreylos2023-01-18 | A not-so-brief tutorial on how to use Vrui with a Valve Index VR headset and Index controllers, using the default configuration shipped with the Vrui package. Uses the Nanotech Construction Kit as an example application.
0:00 Intro, finger tracking 0:40 3D navigation (translation, rotation) 2:00 3D navigation (scaling) 5:25 GUI interaction (menus) 7:20 GUI interaction (dialog windows) 10:50 GUI interaction (scale bar) 13:00 Dynamic tools (creation) 16:16 Dynamic tools (destruction) 17:40 Dynamic tools (saving input graphs) 18:05 Text entry with QuikWriting 20:06 Recap, outro
Nanotech Construction Kit: https://web.cs.ucdavis.edu/~okreylos/ResDev/NanoTechNew AR Sandbox in UC Davis DataLabokreylos2022-11-03 | Quick video showing the AR Sandbox I just installed at DataLab. This one was donated by the friendly folks at Reactive Digital Systems, http://www.topobox.co
Proper video showing off the box and all the newest AR Sandbox features coming soon. AR Sandbox project page: https://web.cs.ucdavis.edu/~okreylos/ResDev/SARndbox AR Sandbox support forum: http://doc-ok.org/?forum=ar-sandbox-forumHeart Surface Voltage Distributions During Cryoablation Treatment for Atrial Fibrillationokreylos2022-10-29 | Explanation of the source data for a machine learning procedure to predict types of atrial fibrillation (paroxysmal vs. persistent) and medium-term patient outcomes under development at UC Davis DataLab, in collaboration with Drs. Uma Srivatsa and Nipavan Chiamvimonvat, UC Davis Health.IK Avatar Test With Bowokreylos2022-07-01 | Just a test of the current IK avatar code, which still has some bugs, but this is looking decent so far. To quote an eloquent commenter from the previous video: "What is a bow, but a more complex way of throwing?"
The target in frame is 20 meters away; the out-of-frame target is 15 meters away.
Before I get angry comments: ;-) - My Valve Index's built-in microphone is still recording total silence. No idea why. - I know one doesn't "shoot" arrows, but "looses" them. It slipped out. - I changed the quiver position right before filming; should have practiced first.Why Throwing Often Does Not Work In VRokreylos2022-06-29 | I've recently thought about throwing, and why many VR applications or games don't seem to get it quite right. Here I am giving my thoughts on what the underlying causes might be, and how to fix it for a better, by which I mean more intuitive and predictable, throwing experience.
Important note: at 8:57 I say that averaging to remove noise is a bad idea, but I forgot to mention the most important reason why: averaging can get rid of *random* noise, but this noise *is not random, as I explain.*Semi-Automatic Calibration of Non-Aligned Projectionsokreylos2022-06-21 | In this video I am demonstrating a new projection calibration procedure that will be part of Vrui's RoomSetup utility, and lets users quickly calibrate a large screen, even an ad-hoc off-axis projection screen, with the VR tracking system, to show precisely-aligned "mixed reality" projections from arbitrary camera positions. While a VR application is running, the virtual camera position can be set at any time simply by touching a real camera's lens with an input device and pressing a selected button. From that point on, the real camera will show a precisely aligned view of the virtual world.Starlink and Space Debrisokreylos2022-06-18 | A quick video about a visualization of low-Earth orbit space objects I made from NASA/NORAD tracking data, focusing on the more than 2,400 Starlink satellites criss-crossing low-Earth orbit, just because.
Victoria Keddie's web site: http://www.victoriakeddie.com Space-Track.org's web site: space-track.orgPropagation of the Hunga Tonga Eruptions Tsunami through the Pacific Oceanokreylos2022-01-20 | Comparison between observed tsunami arrival times extracted from tide gauge data and a simple propagation model based on a circular wave expanding across the globe at a constant velocity.
en.wikipedia.org/wiki/2022_Hunga_Tonga_eruption_and_tsunamiHoney, I think the dog is brokenokreylos2021-12-29 | ...The Earth - Moon - Sun System, Drawn to Scaleokreylos2021-03-02 | Just what it says on the tin.One More Orbits Pole-to-Pole Circumnavigation, Compared to Pan-Am 50sokreylos2020-08-06 | I thought there was an interesting difference between these two flight routes, so here we go.
One More Orbit's web site: onemoreorbit.comPan-Am Flight 50s Pole-to-Pole Circumnavigation of the Globeokreylos2020-08-06 | I can't believe I only found out about this flight today. My aeronautics nerd credentials have officially been revoked.
Here is the article about the flight I reference in the video: cnn.com/travel/article/pole-to-pole-pan-am-flight-50/index.htmlGreat Circles are Straight Lines (as much as thats possible on a sphere)okreylos2020-05-14 | When flying along a great circle route, pilots do not have to turn their planes left or right to stay on course. But, throughout the flight, the apparent compass heading of the plane will change, because the compass is aligned with the meridian great circles, which are not parallel to each other (they intersect in the north and south poles).
Smithsonian navigation page mentioned in the video: https://timeandnavigation.si.edu/multimedia-asset/great-circle-routeCollaborative VR Experiments in ModLabokreylos2020-02-26 | Early test of new collaboration framework in UC Davis's ModLab. Two users in the same physical space playing with virtual "rope" using the Nanotech Construction Kit. The inverse kinematics-controlled avatars are not fitted to each user yet.
More information: http://www.idav.ucdavis.edu/~okreylos/ResDev/Vrui http://www.idav.ucdavis.edu/~okreylos/ResDev/Collaboration http://modlab.ucdavis.eduSimple Kinetic Gas Simulation Above A Sphereokreylos2020-01-12 | Quick follow-up to my previous video, "Why Does The Vacuum Of Space Not Suck Away Our Atmosphere," youtube.com/watch?v=vwk4mSFFop0 .
In this video, I use the same simulation, but accelerate all particles towards the center of a sphere.Why Does The Vacuum Of Space Not Suck Away Our Atmosphere?okreylos2020-01-11 | Instead of answering the question the usual way, through gas dynamics and thermodynamics, I try answering it with a purely kinetic simulation based on three simple rules. Here's a related video showing the same simulation around a globe, with no side walls: youtu.be/TyVx3UnZbVUHow Curved is the Horizon?okreylos2020-01-10 | When I made a video about long-distance photography about a year ago, I got a lot of comments complaining that my globe model did not exhibit any horizon curvature. Here is why it did not.
Referenced video: youtube.com/watch?v=RK93TfSYeQUDawn Sumner Talking About Mars Curiosity Roverokreylos2019-07-22 | A recording of Dawn Sumner, member of the MSL (Mars Science Laboratory, commonly known as "Mars Curiosity rover") science team, talking about some of the rover's features.
I filmed this (using a mobile phone; I apologize for poor audio and video quality) to test tracked-camera video recording during a filming session we did in the UC Davis ModLab for an upcoming 90 minute National Geographic TV special on Mars exploration.
The Mars rover CAD model was provided by the Jet Propulsion Laboratory (JPL).
The 3D Mars terrain data was reconstructed from images sent back to Earth by the rover's NavCam stereo cameras. The rover CAD model is "parked" exactly where the rover actually stood on Mars while capturing the initial set of source imagery.
The terrain texture was created by projecting images sent back to Earth by the rover's MastCam color camera onto the reconstructed 3D terrain.
Dawn is viewing the 3D rover model and the 3D Mars terrain model using an HTC Vive virtual reality headset, running custom VR visualization software developed at UC Davis.
More information: nasa.gov/mission_pages/msl/index.html mars.nasa.gov/msl/mission/rover/eyesandother https://geology.ucdavis.edu/people/faculty/sumner twitter.com/sumnerd http://modlab.ucdavis.eduAR/VR Sandbox at UC Davis Picnic Day 2019okreylos2019-04-14 | As is tradition for Picnic Day, we rolled out the AR Sandbox as an exhibit inside the Department of Earth & Planetary Sciences. This time, we unveiled the new "VR mode," where users wearing VR headsets can explore the dynamic sand surface in real time and at 1:1 scale.
The small red sphere on the TV display indicates the position of the VR user inside the AR Sandbox. In this clip, a group of users around the AR Sandbox created a high-altitude reservoir, and the VR user wants to experience a dam failure from ground level.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/SARndboxVR Molecular Dynamics Visualizationokreylos2019-04-10 | A simple VR viewer for time-varying molecular dynamics (MD) simulation results. Simulation data kindly provided by Prof. Toby Allen, formerly of UC Davis, now at RMIT University, Melbourne, Australia.Does This Photograph Prove That The Earth Is Flat?okreylos2019-02-27 | Let's put Round Earth Theory to the test by analyzing a stunning long-distance photograph of Mt. San Jacinto, CA, taken from Point Dume, Malibu, 197 kilometers away.
YouTube video where I found the photograph: "Mt San Jacinto from 123 miles in High Res IR on super clear day!", youtube.com/watch?v=KxLwaaU1aNkInverse Kinematics Upper Body Modelokreylos2018-12-20 | Early experiments with an Inverse Kinematics-driven upper body model, based purely on tracking data available from commodity VR headsets, namely head position and orientation, and position and orientation of two hand-held controllers.
This work was inspired by the following recent publication: Parger, M., Schmalstieg, D., Mueller, J.H., and Steinberger, M., "Human Upper-Body Inverse Kinematics for Increased Embodiment in Consumer-Grade Virtual Reality," Symposium on Virtual Reality Software and Technology (VRST '18), November 28-December 1, 2018, Tokyo, Japan. ACM, New York, NY, USA, 10 pages. doi.org/10.1145/3281505.3281529Configuring a VR Environment in Vrui using RoomSetupokreylos2018-12-19 | A video showing the procedure to configure a physical environment for subsequent use of Vrui-based VR applications with an HTC Vive VR headset.
This video is part of a set-up guide for the Vrui VR development toolkit, "Set-up Instructions for Vrui with HTC Vive Head-mounted Display," http://doc-ok.org/?p=1737
More information: Vrui: http://idav.ucdavis.edu/~okreylos/ResDev/VruiVR ProtoShop in CAVEokreylos2018-09-02 | Here's another ancient video from the vault: Interacting with a 3D protein model in the CAVE, using the VR version of ProtoShop. I recorded this one in early 2006.
ProtoShop is a modeling program for proteins, specifically designed to create initial configurations for ab-initio protein structure prediction. It's described in detail in this paper, which won the "Best Application" award at the 2003 IEEE Visualization conference:
Kreylos, O., Max, N.L., Hamann, B., Crivelli, S.N. and Bethel, E.W., "Interactive Protein Manipulation," in: Turk, G., van Wijk, J.J., and Moorhead, R.J., eds., "IEEE Visualization 2003," IEEE Computer Society Press, Los Alamitos, CA, pp. 581-588
ProtoShop has been used in several international protein structure prediction competitions, and was crucial in predicting the structures of several large proteins that were too complex for non-interactive prediction.
More information on (VR) ProtoShop: http://idav.ucdavis.edu/~okreylos/ResDev/ProtoShopAliso Canyon Gas Leak Visualizationokreylos2018-08-07 | Between late October 2015 and early 2016, approximately 97,100 (metric) tonnes of methane and 7,500 (metric) tonnes of ethane were accidentally released from a natural gas storage facility in the greater Los Angeles area (en.wikipedia.org/wiki/Aliso_Canyon_gas_leak).
This video shows a visualization of the methane gas cloud reconstructed from airborne measurements, collected by a small plane between 1:30pm and 3:30pm on November 10th, 2015. The data collection was overseen by UC Davis researcher Dr. Ian Faloona.Lets Play... Starglider Pro!okreylos2018-02-20 | This is a blast from the past. A protected-mode DOS game for VGA/VESA 2.0 graphics adapters and SoundBlaster sound cards I made in the summer of '96 as preparation for my 3D computer graphics oral exam. It's a rip-off of Rainbird's famous mid-80s Starglider game, which was one of my favorites on the Atari ST.
The game and 3D rendering engine were developed from scratch, as an unholy mixture of C++ and 386 assembly for the low-level parts such as fixed-point linear algebra, 2D frame buffer graphics, and multi-source sound mixing.
More information: http://doc-ok.org/?p=1690LiDAR Viewer on Vive with Aerial LiDAR Scanokreylos2017-12-14 | Using LiDAR Viewer to explore and analyze an aerial LiDAR scan of the city of San Francisco and environs. The raw LiDAR data were colorized by mapping a set of aerial photographs onto the 3D point cloud using the images' georeferencing information.
The LiDAR data were collected by UC San Francisco under an ARRA grant, and the aerial images were collected under the National Agricultural Imaging program.
The LiDAR scan contains approximately 1 billion 3D points.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/LiDARLiDAR Viewer on Vive with Terrestrial LiDAR Scanokreylos2017-12-14 | Using LiDAR Viewer to explore and analyze a terrestrial (tripod-based) LiDAR scan of a fresh landslide (Laguna Beach Blue Canyon landslide, Orange County, California, summer 2006).
The LiDAR Data were collected by Dr. Gerald Bawden of the US Geological Survey.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/LiDARSeismic Tomography Data in 3D Visualizer on Viveokreylos2017-12-14 | Using 3D Visualizer to explore a seismic tomography dataset of the western US.
The dataset is a 2008 model created by Dr. Richard Allen, UC Berkeley Seismolab. While the data have been made obsolete by newer models integrating more source data, this one is still a good illustration of 3D Visualizer's principle of operation.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/DataExploration http://seismo.berkeley.eduSensor Fusion for Object Trackingokreylos2017-09-02 | Tracking in modern commercial VR systems is based on the principle of sensor fusion, where measurements from multiple independent sensors are combined to estimate the position and orientation of tracked objects with better quality than what can be achieved by using those same sensors in isolation.
This video shows a simulation of a moving and rotating object in two dimensions, tracked by an external absolute measurement system and a relative measurement system integrated into the tracked object. Measurements from these two systems are combined using a non-linear extension of the Kalman filter, yielding a result with low noise, low update latency, and no drift.
More information: en.wikipedia.org/wiki/Kalman_filterFeedback-driven Measurement of Visual Acuityokreylos2017-08-04 | Video showing a repeatable procedure to measure the visual acuity provided by a (screen-based or head-mounted) computer display, based on feedback-driven virtual optometric test charts.
This specific test was performed on a 28" 3840x2160 LCD monitor, viewed from a distance of 31.5", with 16x multisampling.
More information: http://doc-ok.org/?p=1631Mixed Reality Recording with Moving 3D Camera (First Attempt)okreylos2017-08-04 | First trial of recording mixed-reality footage with a tracked 3D camera, using the moving-camera calibration procedure shown in an earlier video. Time synchronization between tracker and 3D video stream is still somewhat off, which causes jitter in the video.
More information: http://doc-ok.org/?p=1623 http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://idav.ucdavis.edu/~okreylos/ResDev/VruiMixed Reality Recording with Static 3D Cameraokreylos2017-07-30 | Using the static camera calibration created in a previous video, we now record the user inside and interacting with a virtual environment. Calibration ensures that real objects recorded with the 3D camera line up well with virtual objects.
This video was entirely created and recorded in-engine, without green screens or any post-processing.
More information: http://doc-ok.org/?p=1623 http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://idav.ucdavis.edu/~okreylos/ResDev/VruiExtrinsic 3D Camera Calibration - Moving Cameraokreylos2017-07-29 | Second video showing the inverse extrinsic calibration procedure, where it is now the 3D camera that is rigidly attached to a tracked object, and the calibration disk is at a fixed position in world space. This setup could, for example, be used to record more dynamic mixed-reality footage of a VR application with a moving camera.
The calibration procedure is very similar, only that now the camera needs to be aimed at the calibration disk from a variety of positions and orientations.
More information: http://doc-ok.org/?p=1623 http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://idav.ucdavis.edu/~okreylos/ResDev/VruiExtrinsic 3D Camera Calibration - Static Cameraokreylos2017-07-28 | Video showing the new extrinsic calibration procedure to align a 3D camera such as Microsoft's Kinect with a 3D tracking system such as HTC Vive's Lighthouse.
A flat disk (a CD/DVD covered in paper on both sides) is attached to a controller or other tracked object, and shown to the camera in several different positions, and several different orientations, throughout the tracked space. As tie points are collected, the software updates the tracker-camera calibration in real time, and finally saves it as the camera's persistent extrinsic calibration.
More information: http://doc-ok.org/?p=1623 http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://idav.ucdavis.edu/~okreylos/ResDev/VruiPlaying Catch in VRokreylos2017-07-13 | While calibrating my 3D camera with respect to my VR headset, I was wondering: would calibration be good enough to play catch while in VR? Fortunately, I had a little helper at hand to find out.
On second thought, this is probably more like playing catch in pass-through augmented reality, but whatever.
More information: http://doc-ok.org/?p=1508 http://idav.ucdavis.edu/~okreylos/ResDev/KinectThe Godzilla Experience at the SF Exploratoriumokreylos2017-04-05 | Ad-hoc video clip from UC Davis' / KeckCAVES' virtual reality exhibit at UC Davis' OneClimate event at the San Francisco Exploratorium.
Featuring a visitor stomping through a high-resolution LiDAR scan of downtown San Francisco and environs, displayed here at 1:500 scale.
More information: http://idav.ucdavis.edu/~okreylos/ResDev http://idav.ucdavis.edu/~okreylos/ResDev/LiDAR http://doc-ok.org/?p=1508 http://doc-ok.org/?p=432Paleoceanography Data in VR Exhibitokreylos2017-04-05 | Ad-hoc video clip recorded while setting up UC Davis' / KeckCAVES' virtual reality exhibit at UC Davis' OneClimate event at the San Francisco Exploratorium on 03/13/2017.
Featuring KeckCAVES post-doc Carlye Peterson interacting with a model of carbon isotope distribution in the global ocean created by Jake Gebbie at Woods Hole Oceanographic Institution.
More information: http://doc-ok.org/?p=1508 http://idav.ucdavis.edu/~okreylos/ResDevCollaborative Data Analysis between CAVE and Viveokreylos2017-02-09 | Clip from a collaborative visualization session at KeckCAVES, between the CAVE and an HTC Vive head-mounted VR system. This clip was recorded by post-doc Dr. Carlye Peterson during a recent meeting of a multi-campus NSF-funded paleoceanography project involving UC Davis, UC Santa Barbara, and the Woods Hole Oceanographic Institute. The project is investigating changes in global ocean flow patterns in response to change in global climate between the last ice age and today, based on differences of stable isotope distributions in benthic core samples collected at hundreds of sites across the globe.
The visualization software shown in this clip is 3D Visualizer, looking at combinations of 3D isotope field reconstructions superimposed over a high-resolution global bathymetry model. Collaboration between individual VR systems (in this case CAVE and Vive) is supported by the Vrui VR toolkit's collaboration infrastructure add-on. Remote users are embedded into each VR system as real-time, pseudo-holographic 3D video avatars captured by one or more 3D cameras integrated into each VR system.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/Vrui http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://idav.ucdavis.edu/~okreylos/ResDev/Collaboration http://idav.ucdavis.edu/~okreylos/ResDev/DataExploration3D Visualizer on Viveokreylos2017-02-08 | Using 3D Visualizer in the HTC Vive head-mounted VR system to analyze a 3D medical CAT scan.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/DataExploration http://idav.ucdavis.edu/~okreylos/ResDev/Vrui http://doc-ok.org/?p=1508Actually, its a highly sophisticated interlocking brick systemokreylos2016-10-18 | Yet another mixed-reality "Vrui on Vive" video, for no other reason than they're just so darn easy to make.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/Vrui http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://doc-ok.org/?p=1508Vrui on Viveokreylos2016-10-17 | First recording of a Vrui toy application, ClusterJello, running on an HTC Vive head-mounted display on Linux. This video was recorded from inside the application, using a second-generation Microsoft Kinect camera (Kinect-for-Xbox-One) to integrate the real user into the virtual environment.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/Vrui http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://doc-ok.org/?p=1508Lighthouse Tracking Examined - Headset at Restokreylos2016-05-25 | First video looking in detail at HTC Vive's Lighthouse tracking system: residual noise and anisotropy when the headset is in a fixed position.
Source article: http://doc-ok.org/?p=1478Lighthouse Tracking Examined - Headset in Motionokreylos2016-05-25 | Second video looking in detail at HTC Vive's Lighthouse tracking system: dead reckoning inertial tracking and laser-based drift correction with headset in motion.
Source article: http://doc-ok.org/?p=1478Lighthouse Tracking Examined - Controller in Motionokreylos2016-05-25 | Third video looking in detail at HTC Vive's Lighthouse tracking system: interleaved X and Y laser-based drift correction with controller in motion.
Correction: I made a mistake at 0:55. The controllers are not connected to the host PC via Bluetooth, but via a custom 2.4 GHz radio protocol routed through the headset.AR/VR Sandboxokreylos2016-04-13 | First experiment with dual-mode AR Sandbox, combining an AR projection-mapped display inside the physical sandbox, and a virtual 3D / VR view of the same terrain and water flow on a secondary display (in this case a small desktop monitor).
More information: http://idav.ucdavis.edu/~okreylos/ResDev/SARndbox http://arsandbox.orgAR Sandbox Update Latency Explainedokreylos2016-04-10 | Whenever some video or GIF of the AR Sandbox gets exposure on social media, there's a lot of (wrong) speculation about its latency, or good advice on how I should learn programming and optimize my slow code. :)
So here's the reason behind the AR Sandbox's default 1s topography update delay, explained once and for all.
More information:
http://idav.ucdavis.edu/~okreylos/ResDev/SARndbox http://arsandbox.orgPlayStation Move Tracking Testokreylos2015-09-30 | Test of new algorithm to optically track a PlayStation Move motion controller in three dimensions using a standard color webcam (or PlayStation Eye camera).
The algorithm is based on blob extraction, and fitting a cone with apex at the camera's center of projection to the boundary of the extracted blob to envelop the PS Move's glowing sphere.
Cone fitting appears to have low noise, and be robust against occlusion.
Algorithm details: http://doc-ok.org/?p=1599 Related video: Sensor Fusion for Object Tracking, youtube.com/watch?v=-nsylEpgVekLife-size 3D Video Avatarsokreylos2015-08-31 | Projecting life-size pseudo-holographic 3D video avatars into an immersive virtual reality environment. The avatars were collected using three first-generation Microsoft Kinect-for-Xbox-360 cameras and custom software, and played back in a CAVE VR environment using the Vrui VR toolkit and the Kinect 3D video capture/processing framework.
Filmed with a standard video camera and no post-processing of any kind. Everything visible in the video was visible to the real person in the CAVE.
Chair is for scale.
More information: http://idav.ucdavis.edu/~okreylos/ResDev/Kinect http://idav.ucdavis.edu/~okreylos/ResDev/Vrui http://idav.ucdavis.edu/~okreylos/ResDev/KeckCAVESLocomotion in Virtual Realityokreylos2015-07-28 | Recording of the presentation I gave at the most recent Sacramento VR Meetup (SacVR) on Friday, July 24th in the Hacker Lab in Rocklin, CA. The meetup was organized by Matt "Stompz" Carrell and Brian "Bullardo" Bullard, co-hosts of the PodVR podcast.
This presentation looks at the fundamentals of locomotion (or navigation) in virtual reality, presents a framework of treating real and virtual locomotion uniformly, and examines how the same framework can be employed to address important issues caused by locomotion, such as simulator sickness and boundary violations.