Forum Replies Created

Viewing 15 posts - 1 through 15 (of 473 total)
  • Author
    Posts
  • in reply to: Save Your setup #118570

    Oliver Kreylos
    Keymaster

    Best way to proceed is to bind the tool, then select “Save Input Graph” from the Device sub-menu of Vrui’s system menu. That will write a configuration file fragment with the name of the tool class, and the button(s) to which it’s bound. You can use those in your main Vrui.cfg file.

    in reply to: shader water flow simuation #118568

    Oliver Kreylos
    Keymaster

    I’m citing the paper describing the algorithm I use on the main AR Sandbox page.

    There is also a paper describing a GPU implementation of that algorithm that’s very similar to mine. Google for “Saint Venant GPU implementation”. It’s by Brodtkorb et al.

    in reply to: Sandbox image distortion – Kinect 1414 #118567

    Oliver Kreylos
    Keymaster

    I’ve never seen that before. It looks like your Kinect is reporting wrong intrinsic calibration parameters. Try running “sudo KinectUtil -getCalib 0” again, and (temporarily) remove your depth calibration parameters from the Kinect package’s configuration directory (by default /usr/local/Vrui-<version>/Kinect-<version>).

    Then run “KinectViewer -compress -c 0” (not RawKinectViewer) and see if you are getting an undistorted 3D reconstruction of your environment.

    in reply to: Uncertain problem with new sandbox #118566

    Oliver Kreylos
    Keymaster

    The second-generation Kinect (for Xbox One) is rather flaky, at least compared to the first-generation one.

    It’s normal for the Kinect v2’s depth image to be pincushioned — unlike the first Kinect, the second one has lens distortion correction parameters in firmware — but the depth image showing all white means the software doesn’t receive depth data. That’s a connection issue at the USB level, potentially due to a bad USB adapter cable.

    in reply to: ARSandox-Projector Calibration? #118565

    Oliver Kreylos
    Keymaster

    The yellow box, and the image blobs inside the yellow box, are not meant to line up with your sandbox or calibration targets. They are just there to visually check for mismatches between your current sand surface and the captured background, and to check if your target disk gets recognized (yellow disk turns green).

    Align you camera and projector so that the camera sees the entire box, and so that the projector projects everywhere inside the box. Then calibrate, ignore the yellow rectangle, and run the main AR Sandbox application afterwards with -fpv. Everything should line up then.

    in reply to: Could not find resource libScriptExecutorTool.so #118564

    Oliver Kreylos
    Keymaster

    One of your error messages refers to Vrui-4.2, which does not contain the script executor tool. I recommend updating to the current software versions across the board. Don’t forget to back up your configuration files!

    You can change “viscosity” through a slider in the water simulation dialog, or through commands to the AR Sandbox’s control pipe. I’m putting viscosity in quotes because you’re actually changing velocity attenuation, which is close enough in visible effect to stand in as a proxy for viscosity.

    in reply to: Calibration process checking #118561

    Oliver Kreylos
    Keymaster

    1) CalibrateProjector always starts from scratch. It ignores any previous ProjectorMatrix.dat.

    2) Yes, it should.

    3) Do you mean after you collected an additional 12 tie points? If not, see 1).

    4) Generally, yes. CalibrateProjector only accepts tie points if they fall within the box boundaries. Capturing corners in the wrong order would result in most or all tie points being rejected.

    in reply to: Error while loading shared libraries #118560

    Oliver Kreylos
    Keymaster

    I don’t know. Did you run Vrui’s installation script, and did the spinning globe show up? Which version of the Kinect package did you download?

    Make sure that you were following these instructions, and not an outdated version.

    in reply to: Is this a suitable short throw projector? #118559

    Oliver Kreylos
    Keymaster

    That’s not going to be working well. The projector’s brightness is 25 lumens. We recommend using projectors of 3000 lumens, or ideally more. The image will be almost invisibly dim.

    in reply to: Complete Installation Instructions #118557

    Oliver Kreylos
    Keymaster

    It will work, but 72cm x 54cm is on the small side for a sandbox. The problem with normal-throw projectors is that the height they need typically requires folding their light paths with a mirror, which works, but adds complexity and reduces stability.

    in reply to: Off-the-shelf desktop PC for AR Sandbox #118531

    Oliver Kreylos
    Keymaster

    “OPENGL vendor string:VMWare,Inc.”

    It looks like you installed Linux inside a virtual machine. That will not work, because Linux won’t be able to directly access the graphics card, hence no image over HDMI.

    in reply to: GTX 1060 Driver Issues #118510

    Oliver Kreylos
    Keymaster

    I’ve recently run across a similar problem. First off, don’t ignore and continue; things won’t work. The AR Sandbox software won’t be able to access the graphics card’s full feature set.

    Check your BIOS settings next time you reboot. If your boot options are set to “secure boot,” or sometimes it’s called something like “boot for Windows,” then try switching to legacy boot mode, which might unfortunately require a re-install of Linux — try if you can boot into your existing Linux installation first.

    While “secure boot” should work with Linux Mint, there might be the odd motherboard where it causes issues. Not being able to access the graphics card can be one of those issues.

    If you’re already in “legacy mode,” switch to the other mode.

    in reply to: RealSense V2.0 #118450

    Oliver Kreylos
    Keymaster

    If you have a RealSense API v1 camera, i.e., anything before D415/D435, and installed Intel’s RealSense driver before building the Kinect package, it should just work.

    If you have a D415/D435 camera, it will not work. I don’t have a wrapper for the new driver library for lack of hardware.

    in reply to: Can I turn off ability make rain by hand? #118447

    Oliver Kreylos
    Keymaster

    You can turn off the water simulation entirely by adding -ws 0.0 0 to SARndbox’s command line, but right now there is no switch to only turn off hand detection.

    in reply to: Theoretical background for Calibration method #118416

    Oliver Kreylos
    Keymaster

    Base plane equation:

    1. Collect a bunch of 3D points d_i in depth image space from the camera’s depth image.

    2. Convert depth image-space points to metric camera space using camera’s intrinsic depth un-projection matrix (read from camera firmware): c_i = DP * d_i.

    3. Find the plane equation (nx, ny, nz) * c_i = o that best fits all points c_i using a standard least-squares linear system solver A^T * A * x = A^T * b.

    Projector calibration matrix:

    1. Collect a set of tie points that associate a 2D point p_i in projector image space with a 3D point c_i in metric camera space.

    2. Create an over-determined linear system for (p_ix * w_i, p_iy * w_i) = H_2 * c_i where H = (h0, …, h3, h4, …, h7, h8, …, h11) is an unknown 3×4 matrix, H_2 is the 2×4 matrix consisting of the upper two rows of H, and w_i = h8*c_ix + h9*c_iy + h10*c_iz + h11 is the homogeneous weight of H * (c_ix, c_iy, c_iz, 1).

    3. Solve the system A^T * A * x = 0 by finding the eigenvector of A^T * A that has the smallest eigenvalue.

    4. Extend the resulting matrix H to an OpenGL projection matrix by inserting a third row (0, 0, 0, -1) and pre-multiplying it with the inverse of a viewport matrix that maps the projector’s screen rectangle to [-1, 1] in both x and y, and the camera-space tie points’ z range, after multiplication with the extended H, to [-0.5, 0.5] in z. Z maps to [-0.5, 0.5] instead of [-1, 1] to avoid clipping away geometry that is lower or higher than the lowest or highest tie point, respectively.

Viewing 15 posts - 1 through 15 (of 473 total)