Unity 5.2.1: Three quick tips for improving the VR user experience

For demos that I work on, there are three simple things that I always do to create a better user experience:

• make sure the Oculus health and safety warning (HSW) has been dismissed before any other information is displayed
• give the user the option to re-center their avatar after they’ve put the headset on and settled in a comfortable position
• encourage the user to create a profile

If you are a regular reader of this blog, you know this isn't the first time I've covered these topics. However, now that Unity includes native VR support I wanted to revisit these tips and show how to do them with Unity 5.2.1, the 0.7 runtime, and the Oculus Utilities for Unity 0.1-beta package.

Knowing when the HSW has been dismissed

The HSW is a big rectangle centered in front of the user. While it is semi-transparent, it blocks the user’s view significantly. For that reason, I like to make sure that is has been dismissed before displaying anything the user needs to interact with.

The Oculus Utilities for Unity 0.1-beta package provides a way to check to see if the HSW is still displayed:

OVRManager.isHSWDisplayed

This returns true when the HSW is displayed and false when it is not. Note that if you are running the application in the Editor, you won't see the HSW in the Editor window, however, the HSW will appear in the Rift view.

Re-centering the avatar

It is helpful to give users the option to re-center their virtual selves and this is one of the functions available as part of the Unity native VR implementation. 

 To re-center, add the VR name space and use:

VR.InputTracking.Recenter()

Encouraging the user to create a profile

If the user has not created a profile, the user may experience discomfort because the default IPD or height is different from their own. In previous versions,  you could get the name of the profile in use, and if the name returned was "default," you would know that the user had not created a profile. Unfortunately, I’m not seeing a way to do that with the Oculus Utilities for Unity 0.1-beta package. I tried  using OVRManager.profile.username, but it returns "Oculus User" and not the name from the user profile. Looking at OVRProfile, it appears that only ipd, eyeHeight, and eyeDepth are retrieved from the current user profile (Note: you can get the user's eye height and IPD  using OVRManager.profile.eyeHeight and OVRManager.profile.ipd.)

For now, I’ll just stress the importance of creating a profile in the documentation. If anyone knows how to get the current user name, please comment!

Unity 4: Knowing which user profile is in use

Previous versions of the Unity Integration package did not include a call for getting the user profile name. As of 0.4.3, it is now possible get the the user profile name. To know which profile is being used, you can use GetString()found in the OVRManager.cs script.

public string GetString(string propertyName, string defaultVal = null)

Below is a simple example script (report.cs) that uses this method to print out the name of the current user profile to the console. To use this script,  attach it to an empty game object in a scene that is using the OVRCameraRig or OVRPlayerController prefab. With the Rift connected and powered on, run the scene in the Unity Editor. If default is returned, no user profile has been found.


using UnityEngine;
using System.Collections;
using Ovr;

public class report : MonoBehaviour {
    void Start () {
     Debug.Log (OVRManager.capiHmd.GetString(Hmd.OVR_KEY_USER, "")) 
    }
}

The GetString()method found in the OVRManager.cs script method is used to get the profile values for the current HMD. The OVRManager.cs script gets a reference to the current HMD, capiHmd. The Hmd class, defined in OvrCapi.cs, provides a number of constants that you can use to get user profile information for the current HMD. In this example, I used OVR_KEY_USER to get the profile name. You could also get the user’s height (OVR_KEY_PLAYER_HEIGHT), IPD (OVR_KEY_IPD) or gender (OVR_KEY_GENDER), for example.

0.4 SDK: Users of unknown gender now have a gender of “Unknown”

Oculus recently released the 0.4 version of the SDK.  I am primarily a Mac developer and the fact that it isn’t available for the Mac yet is a big disappointment to me. So while I am impatiently waiting for the Mac version, I’ll poke around the Windows version. As the default profile settings were an irritation to me previously, I checked to see if Oculus made changes to the default profile settings and I am pleased to see that they have:

#define OVR_DEFAULT_GENDER                  "Unknown"

That’s right. Users who have not yet created a profile are no longer assumed to be “male”. Instead the default matches reality - when the user’s gender is unknown because the user hasn’t specified a gender, the SDK now returns a gender of “Unknown”.

This is a good step as you will no longer get false data from the SDK. Let's take a closer look at the profile default values

// Default measurements empirically determined at Oculus to make us happy

// The neck model numbers were derived as an average of the male and female averages from ANSUR-88

// NECK_TO_EYE_HORIZONTAL = H22 - H43 = INFRAORBITALE_BACK_OF_HEAD - TRAGION_BACK_OF_HEAD

// NECK_TO_EYE_VERTICAL = H21 - H15 = GONION_TOP_OF_HEAD - ECTOORBITALE_TOP_OF_HEAD

// These were determined to be the best in a small user study, clearly beating out the previous default values

#define OVR_DEFAULT_GENDER                  "Unknown"
#define OVR_DEFAULT_PLAYER_HEIGHT           1.778f
#define OVR_DEFAULT_EYE_HEIGHT              1.675f
#define OVR_DEFAULT_IPD                     0.064f
#define OVR_DEFAULT_NECK_TO_EYE_HORIZONTAL  0.0805f
#define OVR_DEFAULT_NECK_TO_EYE_VERTICAL    0.075f

#define OVR_DEFAULT_EYE_RELIEF_DIAL         3

It is also good to see that the "neck model numbers were derived as an average of the male and female averages." However, the height here remains as it has in past SDK versions at 1.778f - the average height of an adult male in the US. I'm a little wary of this value as Oculus doesn't indicate how varied the user pool used to determine this value was. They simply say "a small user study." Was this a varied user pool comprised equally of men and women? How varied were the heights of those in the user pool? Without that information or further study, I can't be sure that these values don't introduce bias and it is something I will keep track of in my own user tests.

I've been keeping such a close eye on this issue because I feel that what the writer Octavia Butler said about science fiction applies here and now to VR.

 "There are no real walls around science fiction. We can build them, but they’re not there naturally."
-- Octavia Butler

 There are no real walls around VR. Let's do what we can to not build those walls. VR is for everyone.

Unity 4: Using the player eye height from the user's profile

I had been planning on writing a post on setting the default character eye height in Unity a while ago but I got side tracked and then Oculus put out the preview version of the 0.3 SDK and Unity Integration package. The first preview version didn’t work for the Mac so, although I had read there were some significant changes, I wasn’t able to test them out. Now that it is available on the Mac and I’ve had some time to play with it, I wanted to come back to the character default height question.

The big change  for character height from version 0.2 to 0.3 is that the player eye height set in the Oculus Profile tool is now used by the OVRCamraController script by default to set the character eye height.

Previously if you wanted to use the player's height as set in the user profile, you needed to go in to the Inspector for the OVRCameraController script (attached to the OVRCameraController prefab) and check the box for Use Player Eye Hght. As of version 0.3, this box is checked by default.

Assuming that the player has created a user profile, this makes it easy to have a character of the player’s actual height and, even if a profile isn’t found, the SDK provides values for a default profile. But as we looked at in another post, Working around the SDK default profile setting for gender,  there are issues with those default values, as they are for what Oculus terms the "common user" (a.k.a average adult male) and not for the average human.

If the profile is currently set to the default, the solutions we looked at there included documentation, changing the SDK values, and giving the user an option to set a profile. Like working directly with the SDK, when developing with Unity, emphasizing in the documentation that a profile needs to be set is still a big part of the solution (and a good idea anyway). And, like working directly with the SDK, changing the default values is still not a good solution.

But unlike working directly with the SDK, when working with Unity, checking for the profile used is problematic. When using the SDK directly, there is a call to get the name of the profile being used.

ovrHmd_GetString(hmd, OVR_KEY_USER, "")

Unfortunately, the Unity integration package does not appear to to include a similar call for getting the user profile name. The OVRDevice script provides the following functions to get profile data:

GetPlayerEyeHeight(ref float eyeHeight);
GetIPD(ref float IPD);
IsMagCalibrated();
IsYawCorrectionEnabled();

As you can see, there isn't a call to get the name of the profile in use. So, what to do? One suggestion I saw on the Oculus forums, was to at least warn the user that the headset has has not been calibrated. You can do that by checking if magnetic calibration and yaw correction are false using OVRDevice.IsMagCalibrated() and OVRDevice.IsYawCorrectionEnabled().

While this is a good start, it would be nice if there was an easy way to allow users to see which profile is in use and to allow them to switch between available profiles.