{"id":188,"date":"2017-12-16T22:47:09","date_gmt":"2017-12-16T22:47:09","guid":{"rendered":"http:\/\/www.exhaliastudios.com\/Demo\/?p=188"},"modified":"2017-12-22T16:38:49","modified_gmt":"2017-12-22T16:38:49","slug":"capstone-walk-in-place-mechanic","status":"publish","type":"post","link":"https:\/\/www.exhaliastudios.com\/Demo\/capstone-walk-in-place-mechanic\/","title":{"rendered":"Unity\/VR Capstone Walk-in-Place Mechanic"},"content":{"rendered":"

The major development work for my Udacity VR Developer Nanodegree capstone was in developing a walk-in-place mechanic for the HTC Vive. I have previously tried out an arm swing mechanic that I did not care for, and induced nausea in my husband. To begin I did one of the things I do best: collect data! (I will always be a scientist at heart.)\u00a0 I had decided that I did not want to require the use of controllers for the walk. This would free them up for other uses. In order to collect data on the headset, I wrote a simple reporting script:<\/p>\n

using<\/code> System.Collections;<\/code><\/div>\n
using<\/code> System.Collections.Generic;<\/code><\/div>\n
using<\/code> UnityEngine;<\/code><\/div>\n
using<\/code> System.IO;<\/code><\/div>\n
<\/div>\n
public<\/code> class<\/code> Reporting : MonoBehaviour {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>string<\/code> path = <\/code>\"Assets\/Logs.txt\"<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>Vector3 current;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>Vector3 previous;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>Vector3 delta;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ Use this for initialization<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>void<\/code> Start () {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>StreamWriter writer = <\/code>new<\/code> StreamWriter(path, <\/code>true<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>writer.WriteLine(<\/code>\"transform x, transform y, transform z, delta x, delta y, delta z\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>writer.Close();<\/code><\/div>\n
\u00a0 \u00a0 \u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>current = transform.localPosition;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>previous = transform.localPosition;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ Update is called once per frame<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>void<\/code> Update () {<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>\/\/Write some text to the test.txt file<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>StreamWriter writer = <\/code>new<\/code> StreamWriter(path, <\/code>true<\/code>);<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>current = transform.localPosition;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>vel = (current - previous) \/ Time.deltaTime;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>writer.WriteLine(transform.localPosition.x + <\/code>\",\"<\/code>+ transform.localPosition.y+ <\/code>\",\"<\/code>+ transform.localPosition.z + <\/code>\",\"<\/code> + delta.x + <\/code>\",\"<\/code> + delta.y + <\/code>\",\"<\/code> + delta.z);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>writer.Close();<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>previous = transform.localPosition;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
}<\/code><\/div>\n
<\/div>\n
This collected a ton of data. I had several people wear the head and walk in place. Then I started analyzing. I graphed movement on each axis against each other axis:<\/div>\n
<\/div>\n

X vs Y<\/h3>\n

\"\"<\/a><\/p>\n

X vs Z<\/h3>\n

\"\"<\/a><\/p>\n

Y vs Z<\/h3>\n

\"\"<\/a>Then I graphed each position vs time:<\/p>\n

X<\/h3>\n

\"\"<\/a><\/p>\n

Y<\/h3>\n

\"\"<\/a><\/p>\n

Z<\/h3>\n

\"\"<\/a><\/p>\n

 <\/p>\n

I decided that I didn’t want to use straight transform data as it was fairly volatile, especially if the player wasn’t walking exactly in place. I had also collected a change in position over subsequent frames.<\/p>\n

Delta X<\/h3>\n

\"\"<\/a><\/p>\n

Delta Y<\/h3>\n

\"\"<\/a><\/p>\n

Delta Z<\/h3>\n

\"\"<\/a><\/p>\n

Based on this data it seemed like delta x would be the best measurement to base a step detection algorithm. I created an algorithm that detects the change of delta x from a negative value to a positive one. Each of these is assumed to be a step. What I actually found when I implemented this was that it worked beautifully… unless the player turned their head rapidly from side to side. Since I wanted users to be able to look around during the experience, this wasn’t going to work. Fortunately, it did work when applied the the delta y variable. This had the added advantage of allowing users to simply bob their heads if they didn’t want to actually walk, while still allowing them to look around.<\/p>\n

The second part of walking was to move the player each time a step was detected. I opted to use one of the controllers as a forward pointer, allowing the player to look around while walking. The movement of the player is a bit jerky, but I found that this was less likely to cause VR sickness in the users than if the movement was smoothed. In a future iteration I would both like to be able to calibrate the step detection threshold for each user and allow the user to control the degree to which movement is smoothed out.<\/p>\n","protected":false},"excerpt":{"rendered":"

The major development work for my Udacity VR Developer Nanodegree capstone was in developing a walk-in-place mechanic for the HTC Vive. I have previously tried out an arm swing mechanic that I did not care for, and induced nausea in my husband. To begin I did one of the things I do best: collect data!Continue reading “Unity\/VR Capstone Walk-in-Place Mechanic”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":190,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[14,13],"tags":[],"class_list":["post-188","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-unity","category-vr-development","entry"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.exhaliastudios.com\/Demo\/wp-content\/uploads\/2017\/12\/deltax.png?fit=1396%2C711&ssl=1","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p68Qgg-32","jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/posts\/188","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/comments?post=188"}],"version-history":[{"count":5,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/posts\/188\/revisions"}],"predecessor-version":[{"id":227,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/posts\/188\/revisions\/227"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/media\/190"}],"wp:attachment":[{"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/media?parent=188"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/categories?post=188"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.exhaliastudios.com\/Demo\/wp-json\/wp\/v2\/tags?post=188"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}