Body proportions configuration
SlimeVR creates a virtual skeleton to compute positions from the data it receives from your trackers. As part of the setup procedure, you will be required to provide measurements (in cm) for various body parts in order for SlimeVR to compute its skeleton accurately to your real body.
Measurements
 | Torso length The torso length is from your shoulders to your pelvis. Chest distance The chest distance is from your shoulders to around the midpoint of your torso (around the bottom of your sternum). Waist distance The waist distance is from your waist to your hip (pelvis). Hips width The hips width value is the distance between your femurs. Legs length The legs length value is the full length of your legs, from your pelvis to your ankle. Knee height The knee height value is from the knee to your ankle. Foot length The foot length value is the length of your foot, from your ankle to your toes. Head shift The head shift value is from your headset to about the middle of your head. Neck length The neck length value is the distance from about the middle of your head to your shoulders. Hip offset / Foot shift These values offset your real trackers from virtual one, if your avatar has non-human or unusual proportions. A good example of this use is in avatars with digitigrade legs that may have the foot further out or back. Skeleton offset The Skeleton offset value offsets all your trackers from their physical position forward or backwards. This can be left untouched unless you need it. |
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
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.
How to use
Make sure the headset is ON and on your head while doing this.
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.
How it works
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.
Configuration documentation
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 |
|---|---|---|---|
sampleCount | Integer | 1000 | The number of pose samples to record |
sampleRateMs | Long Integer | 20 | The millisecond interval between each sample to record |
saveRecordings | Boolean | False | When true, recordings will automatically be saved |
minimumDataDistance | Integer | 2 | The minimum distance between samples to be used while adjusting |
maximumDataDistance | Integer | 32 | The maximum distance between samples to be used while adjusting |
epochCount | Integer | 5 | The number of epochs (full loops) to iterate over the data |
adjustRate | Float | 2.5 | The factor to adjust the values by each iteration |
adjustRateDecay | Float | 1.01 | The factor to decay the adjust rate by each epoch (divided by this value) |
slideErrorFactor | Float | 1.0 | The factor of which the foot slide error is used in the error calculation |
offsetErrorFactor | Float | 0.0 | The factor of which the foot offset error is used in the error calculation |
proportionErrorFactor | Float | 0.2 | The factor of which the body proportion error is used in the error calculation |
heightErrorFactor | Float | 0.1 | The factor of which the body height error is used in the error calculation |
positionErrorFactor | Float | 0.0 | The factor of which the absolute position error is used in the error calculation |
positionOffsetErrorFactor | Float | 0.0 | The factor of which the absolute position offset error is used in the error calculation |
calculateInitialError | Boolean | True | When true, the initial error over the data is reported as epoch 0 |
manualTargetHeight | Float | -1.0 | 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 |
Configuring body proportions manually
All this configuration can be done from SteamVR dashboard or in VRChat (in front of a mirror). All measurements are in centimeters. Press + or - 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 it will influence your results: mounting page:
You can use a mirror in VRChat to see your trackers’ positions. However, compare SteamVR tracker position to IRL joint’s position, not your VRChat avatar’s joints positions.
Alternatively, you can use the SlimeVR Overlay in SteamVR to visualize your bones.
Make sure to adjust the values from the top-down.
Head shift (8-12)
Shake your head left to right as if you’re disagreeing. Adjust your head offset until any movement is negligible. All trackers should stay in place.
Neck Length (8-14)
Move your head up and down as if you’re nodding OR tilt your head to the left and right like a cute, confused, dog. Adjust your neck length until any movement is negligible. All trackers should stay in place.
Torso length (50-70)
Modify the value until your SteamVR waist tracker lines up with your belt line (you can use your controller to line them up).
Chest (25-40) and waist (2-6) (when using additional spine trackers)
Sit down hunched and modify values until waist tracker is closest to hip.
Legs (80-100)
Modify until trackers line up vertically with your real feet.
Knees (45-60)
Bend your knees slightly while keeping your back straight and modify the value until your feet move the least amount possible OR sit down and modify until your feet touch the floor (not floating above ground).
Feet (when using feet extensions)
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.
Hips width (26-32)
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.
Hip offset (0)
Keep at 0 unless you have a particular problem with your avatar.
Skeleton offset (0)
Keep at 0 unless you have a particular problem with your avatar.
Shoulders distance (4-10) and Shoulders width (30-42)
Set Upper arm length to 0 and adjust the values until the elbow trackers are on your shoulders.
Upper/Lower arm distance (20-35)
Adjust so that SteamVR tracker is on your elbow.
Controller distance z (10-20) and Controller distance y (2-8)
Rotate wrist and adjust until elbow tracker has the least amount of sliding.
Elbow offset (0)
Keep at 0 unless you have arm tracking problems using lower + upper arm tracking from controller.
Next step - Setting up the reset bindings
Created by Butterscotch!#7878, Eiren and CalliePepper#0666, edited and styled by CalliePepper#0666, Erimel#7159 and Emojikage#3095. Video by adigyran#1121 with help of MightyGood#1341.