SlimeVR creates a virtual skeleton for applying data it receives from your trackers, in order to pass relevant data to your HMD. As part of the setup procedure, you will be required to provide measurements (in cm) for various lengths for the rotations of your trackers to be read correctly.
The torso length is from your shoulders to your pelvis.
The chest distance is from the shoulders to around the midpoint of your torso (around the bottom of your sternum).
The waist distance is from the waist to the hip (on the pelvis).
The hips width value is the distance between your femurs.
The legs length value is the full length of your legs, from your pelvis to your ankles.
The knee height value is from the knee to your ankles.
The foot length value is your foot length, from your ankles to your toes.
The head offset value is from your headset to about the middle of your head.
The neck length value is from about the middle of your head to your shoulders.
Hip offset / Foot offset
These values offset your real hip from virtual one, if your avatar has non human or unusual proportions. A good example of this in use is avatars with digitigrade legs that don't have a flat foot.
While these values can be inputted directly into the SlimeVR server, it is recommended you use the skeleton auto-configuration system. Once it is complete, use the measurements above to eyeball the accuracy before finalising the values. There is also an option to visually check within VR at the bottom of this page.
Skeleton auto-configuration removes the need to manually input bone lengths using automatic bone length calculations through recording player movements.
This bypasses the need to manually set the bone lengths, although they can still be fine tuned if needed.
Before using skeleton auto-configuration, you must “reset” your body proportion values by standing straight up and pressing the “Reset All” button under the “Body proportions” section. If this is not done, then the height value used in calculations will be incorrect.
VERY IMPORTANT: During the recording, you must keep your heels in the same position, otherwise the values will be invalid.
To use skeleton auto-configuration, follow these steps:
- Stand straight up and pressing the “Reset All” button under the “Body proportions” section of the SlimeVR server window.
- Locate and press the “Auto” button under the “Body proportions” section to open the skeleton auto-configuration window.
- Stand in front of a chair.
- Keep your heels on the ground in the same position for the duration of recording.
- Press the “Start Recording” on the skeleton auto-configuration window, the text on the button will change to indicate that recording has started - recording will take approximately 20 seconds.
- Move until the text on the button changes back to “Start Recording”, the current best known movements for calibration are as follows:
- Twist upper body left, then lean right (toward toes).
- Twist upper body right then lean left (toward toes).
- Sit down on a chair then stand up.
- Bend down to touch toes then back up.
- Sit down and wiggle knees then stand up.
- Random wiggles and movements.
- When the button text changes to “Start Recording” again, other buttons should become enabled.
- OPTIONAL: If you want to save your recording to be used later, click the “Save Recording” button, this is currently mostly helpful for debugging purposes, to load recordings later, they must be placed in a subdirectory titled “
LoadRecordings” within the SlimeVR server directory.
- To calculate your body proportions from the recording (current or saved) press the “Auto Adjust” button; you should be able to see new values for the lengths of your body reported in cm.
- To use the calculated values, press the “Apply Values” button. If the values do not look right, you can try recording again.
Skeleton auto-configuration works by recording movement data and simulating that movement rapidly while gradually adjusting the bone lengths. When adjusting bone lengths, the algorithm measures the amount the feet slide to know whether it’s doing better or worse with each adjustment. By iterating over the data multiple times, the algorithm is able to obtain reasonable bone length values with minimal foot sliding.
The skeleton auto-configuration algorithm uses classic machine learning technique called gradient descent to acquire the bone length values. First, many samples of movement data are recorded, then using gradient descent, the algorithm gradually adjusts the bone lengths to minimize the error of foot sliding. Error is calculated through multiple different methods, but generally it is formulated to retain the headset’s reported height, “average” human body proportionality, and reduce the amount that the feet slide during movement.
Almost all of the algorithm’s internal values are exposed through the config file, read the following Configuration documentation section to learn more.
All configuration options should be placed in the
vrconfig.yml file and are sub-configs to
autobone, for example:
zoom: 1.0 virtualtrackers: 3 autobone: sampleCount: 1000 slideErrorFactor: 1.0 calculateInitialError: True
|Config Option||Value Type||Default Value||Description|
| ||Integer|| ||The number of pose samples to record|
| ||Long Integer|| ||The millisecond interval between each sample to record|
| ||Boolean|| ||When true, recordings will automatically be saved|
| ||Integer|| ||The minimum distance between samples to be used while adjusting|
| ||Integer|| ||The maximum distance between samples to be used while adjusting|
| ||Integer|| ||The number of epochs (full loops) to iterate over the data|
| ||Float|| ||The factor to adjust the values by each iteration|
| ||Float|| ||The factor to decay the adjust rate by each epoch (divided by this value)|
| ||Float|| ||The factor of which the foot slide error is used in the error calculation|
| ||Float|| ||The factor of which the foot offset error is used in the error calculation|
| ||Float|| ||The factor of which the body proportion error is used in the error calculation|
| ||Float|| ||The factor of which the body height error is used in the error calculation|
| ||Float|| ||The factor of which the absolute position error is used in the error calculation|
| ||Float|| ||The factor of which the absolute position offset error is used in the error calculation|
| ||Boolean|| ||When true, the initial error over the data is reported as epoch 0|
| ||Float|| ||The height to use for the height error calculation, this is calculated automatically when negative but can be overridden with this when set to a positive value in cm|
All this configuration can be done from SteamVR dashboard or in VRChat (in front of a mirror). All measurements are in centimeters. Press
- to change lengths by 1 cm. Pressing Reset will change the value to a default based on the HMDs current height.
MAKE SURE YOU HAVE PROPER MOUNTING BEFORE DOING THIS AS THIS WILL CHANGE YOUR RESULTS.
Make sure your SlimeVR server is up-to-date (update with installer) so you have the same body proportions names listed below.
Make sure to follow this order (configure head first and feet last)
Shake your head left to right as if you’re disagreeing. All trackers should stay in place as you do so, any movement should be negligible. If they move too much, adjust the head offset.
Move your head up and down as if you’re nodding. All trackers should stay in place as you do so, any movement should be negligible. If they move too much, adjust your neck length.
Modify value until your SteamVR waist/hip tracker lines up with your hip bones (you can use your controller to line up your IRL hip and tracker).
Sit down with your back curved (NOT straight) and modify until tracker is closest to hip.
Modify until trackers line up with your IRL feet vertically.
Bend your knees slightly while keeping your back straight and modify until your feet move the least amount possible OR sit down and modify until your feet touch the floor (not floating above ground).
Set “foot length” at 0, change “foot offset” until feet trackers are inside your avatar’s ankles or at the same level horizontally and set “foot length” back to 5.
Default value is good. Can try to tweak to make your leg trackers line up when resetting, but do not increase in the goal of preventing leg crossing.
Keep at 0 unless you have a particular problem with your avatar.
Created by Butterscotch!#7878, Eiren and CalliePepper#0666, edited and styled by CalliePepper#0666 and Emojikage#3095. Video by adigyran#1121 with help of MightyGood#1341.