Manual Skeleton Adjustment

Manual skeleton adjustment is mainly for users who pursue higher effects. Adjusting the skeleton to be consistent with their own will result in a better overall effect (especially for PC users).

In the PC scenario, if you are directly viewing the preview effect, adjusting to the actual size of your body will yield better results. If you are using other software, it is recommended to upload a skeleton that closely matches your real skeleton for better results.

In the VR scenario, if you are a dancing user, adjusting the skeleton to be consistent with your own will yield better results. In other cases, such as wanting to look more like yourself in a sitting or static posture, a skeleton close to the target will be better, but the dynamic effect will relatively worsen! The best state is to keep the virtual character's skeleton consistent with the real person!

Impact of Inconsistent Skeletons

For example: If the skeleton driving the character has significantly longer hands, assuming the virtual character's hands reach the knee position, then when the real person's palms are together, the virtual character's hands will largely overlap to maintain the same posture as the real person.

For VR users, the greater the movement range and the longer the movement time, the easier it is to deviate if the skeleton is inconsistent with their own. For an extreme example, if the VR character's leg height occupies 9/10 of the entire body and this skeleton is uploaded in rebocap, to keep the feet from slipping and the character's height consistent with reality, a real person stepping 60cm to the right might result in the virtual character stepping over 100cm (the virtual skeleton is much longer than the real person). If VR uses the real person's skeleton but uses this long-legged character in RebornVR or VRChat, the problem is that the virtual character's leg movement angle is much smaller than the real person's leg movement angle. In VR, positioning relies on the tracker's position to infer joint angles.

How to Adjust the Skeleton

• Key Trunk Skeleton Adjustment

• For those who do not want to carefully adjust the skeleton, the default skeleton is a standard human skeleton with average dimensions. Adjust the slider marked as 1 in the figure below, which is the height scaling ratio. You can use the left and right buttons for fine-tuning, and the overall effect will not be too bad (the proportions of each joint will not change as a result).

• For users who want to adjust the skeleton to be consistent with their own, you can refer to the figure below and adjust from bottom to top. The right side shows the key skeleton node positions of the character. You can adjust from bottom to top based on the calculated node height. You can use a tape measure to measure the height of each joint relative to the body while standing and adjust the skeleton lengths 2~8 based on this height information.

  

• For VR users, if you want to adjust the skeleton to be consistent with reality, you can refer to the above point 2 for adjustment. If you want to adjust closer to the virtual character (do not enable VRC mode), each virtual point is at the middle height of the skeleton. Adjust based on this information. Of course, you can also upload a model skeleton yourself [but currently there is no fine-tuning capability based on the uploaded skeleton].

• Other Skeleton Adjustments

  Other skeleton adjustments will not affect height. Mainly refer to the literal meaning on the left side of each adjustment. There are three points to note:

  • Marked as 9, VR headset depth. Adjust according to the headset wear. The best state is minimal chest movement when nodding.
  • Marked as 11, leg spacing. This refers to the spacing of the upper leg joints. If the character keeps their legs at a 90-degree angle to the ground, it can be considered the midpoint spacing of the legs.
  • Marked as 12, foot length. It is recommended to set the foot length smaller than reality because the toe joints bend in reality, but currently, rebocap does not have this joint. So it is generally recommended to measure the distance from the bend to the heel.

Manual Skeleton Adjustment Has No Effect

Please check if the skeleton import is applied. Also, for the FBX export function, skeleton adjustment is currently ineffective. It is recommended to use the default skeleton for recording and not upload the skeleton.

Skeleton Import

When to Use Skeleton Import

For users using the VMC protocol and Blender users, it is recommended to use skeleton import. For Reborn, Unity, and UE users, the SDK will automatically register the skeleton, and generally, no secondary import is needed.

For VR users, if you want your static posture to resemble the target virtual character more and do not consider dynamic effects, you can use skeleton import. (Of course, if the current character skeleton is close to your own, you can also import it. In this case, the dynamic effect will be relatively better). Importing the skeleton in VR will scale the entire skeleton based on height.

Advantages of Skeleton Import

Non-VR users importing the skeleton will prevent foot slippage. However, if the imported skeleton is very different from your own, it can easily lead to unnatural leg switching while walking.

How to Import Skeletons

Currently, two formats are supported for import: one is the general VRM format character import, and the other is the skeleton .rebo_skeleton format file exported from Blender. For other formats, please import them into Blender first, and then use the rebocap Blender plugin to export. For specific Blender plugin usage, refer here.

Import Skeleton Information Parsing

The parsing is based on the length of each joint. It is particularly important to note that the total height of the model is estimated by multiplying the height of the neck node (which can generally be considered as the shoulder height) by a coefficient.

If you import a .rebo_skeleton skeleton, you may be prompted: Foot data not configured, standard model foot information will be used. Here is an introduction and explanation of the principle:

Foot data is mainly used for detecting the foot positioning point (specific points can be found in the Blender plugin export documentation). For example, if you tiptoe, the virtual toe point here will contact the ground. If you are uploading a character, it is best to use the mesh toe position of the uploaded character; otherwise, it may cause the toes to be suspended in the air or below the floor. However, this impact is generally small. If there is a significant difference in the foot length ratio of the character and you want better foot performance, you can adjust these points in detail when exporting from Blender.