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OpenVR CHOP

Summary

The OpenVR CHOP receives positional data, frame rendering info, and action data from the OpenVR SDK. Each CHOP can output in one of 5 modes: Sensors, Projection Matrices, Controllers, Frame Timings, and Actions.

Actions

Actions are a set of values that can be bound to controller inputs through SteamVR.

TouchDesigner defines its list of actions and are available to be bound through the SteamVR Binding tool. TouchDesigner provides a default binding for the HTC Vive Controller, but these bindings can be overridden. Bindings for a variety of other devices can also be added.

To add/edit bindings: from the SteamVR menu select "Devices" -> "Controller Input Binding", then select TouchDesigner.exe from the list of available applications. This will open up the binding creation page for TouchDesigner. If the Vive Controller is selected, a default binding will be on the creation page that can be used. Note: for TouchDesigner.exe to appear in the application list OpenVR must be initialized, which means that TouchDesigner must be open and there must be an OpenVR TOP in the network.


SteamVRBindingCreation.png

Available Actions

These are available actions for both left and right controllers, with an explanation of their default binding on HTC Vive Controller:

  • Hand Pose: Transform matrix, bound to the transform of the controller.
  • Trigger: Boolean value, bound to if the trigger is fully pulled.
  • Squeeze: Float value, bound to the current pulled position of the trigger.
  • Grip: Boolean value, bound to the grip buttons (on the side).
  • Trackpad: X/Y value, bound to the position of finger on the trackpad.
  • Trackpad Click: Boolean value, bound to the trackpad button.
  • Trackpad Touch: Boolean value, bound to the trackpad touch.
  • Joystick: X/Y value, unbound on the HTC Vive Controller.
  • Joystick Click: Boolean value, unbound on the HTC Vive Controller.
  • A Button: Boolean value, bound to the Application Menu button.
  • B Button: Boolean value, bound to the System button.

Getting Sensor Data at Higher Rates

By default when running a VR system the file will be throttled to the speed of the VR devices refresh rate by the OpenVR SDK. This helps ensure the low latency output required for a good VR experience. If only controllers/Vive trackers are being used for tracking in a non-VR situation, the file can run and sample those devices at a higher sample rate as long as no OpenVR TOP in the project. If an OpenVR TOP is present anywhere in the project, then playback will be throttled to the VR devices refresh rate.

See also OpenVR, OpenVR TOP, OpenVR SOP, Audio Render CHOP

PythonIcon.pngopenvrCHOP_Class


Parameters - Setup Page

Active active - Control if this node is querying data from the OpenVR driver.  

Output output - - Controls what kind of category of data will be output from this node.

  • Sensor sensor - Output data such as sensor orientation and general information such as render resolution.
  • Projection Matrices projmatrices - Output the projection matrices for each eye.
  • Controllers controllers - Output controller states.
  • Frame Timings frametimings - General information regarding frame rendering.
  • Trackers trackers -

Max Trackers maxtrackers - The maximum number of controller whose data should be output from this node.  

First Tracker firsttracker - The first controller number to be output. For example if this is set to 2 and Max Controllers is 2, then data for controllers 2 and 3 will be output.  

Left Controller lcontroller -  

Right Controller rcontroller -  

Orientation orientation - When doing 'Sensor' output, controls of the orientation channels will be output. By default the units for orientation are 1 unit = 1 meter.  

General Info generalinfo - When doing 'Sensor' output, controls of general information channels will be output, such as render resolution and play area size.  

Near near - When outputting 'Projection Matrices', controls the near plane the projection matrix will be built with.  

Far far - When outputting 'Projection Matrices', controls the far plane the projection matrix will be built with.  

Unit Scale unitscale - OpenVR by default works in a scale where 1 unit = 1 meter. This parameter allows the scale to be changed incase a scene is imported with a different scale.  


Parameters - Common Page

Time Slice timeslice - Turning this on forces the channels to be "Time Sliced". A Time Slice is the time between the last cook frame and the current cook frame.  

Scope scope - To determine which channels get affected, some CHOPs use a Scope string on the Common page.  

Sample Rate Match srselect - - Handle cases where multiple input CHOPs' sample rates are different. When Resampling occurs, the curves are interpolated according to the Interpolation Method Option, or "Linear" if the Interpolate Options are not available.

  • Resample At First Input's Rate first - Use rate of first input to resample others.
  • Resample At Maximum Rate max - Resample to the highest sample rate.
  • Resample At Minimum Rate min - Resample to the lowest sample rate.
  • Error If Rates Differ err - Doesn't accept conflicting sample rates.

Export Method exportmethod - - This will determine how to connect the CHOP channel to the parameter. Refer to the Export article for more information.

  • DAT Table by Index datindex - Uses the docked DAT table and references the channel via the index of the channel in the CHOP.
  • DAT Table by Name datname - Uses the docked DAT table and references the channel via the name of the channel in the CHOP.
  • Channel Name is Path:Parameter autoname - The channel is the full destination of where to export to, such has geo1/transform1:tx.

Export Root autoexportroot - This path points to the root node where all of the paths that exporting by Channel Name is Path:Parameter are relative to.  

Export Table exporttable - The DAT used to hold the export information when using the DAT Table Export Methods (See above).  

TouchDesigner Build: