Great question! This is a known challenge with Spine physics constraints — when you move a parent bone (like a "camera" bone), the physics constraints on child bones will react to that movement, which may not be what you want.
Unfortunately, there is no built-in setting in Spine to designate that a specific parent bone's movement should not influence physics constraints on child bones.
However, here are some approaches you can consider:
Use the actor/skeleton scale/position instead of a bone
Rather than using a parent bone to simulate camera movement, it is better to transform the skeleton or actor at the runtime/engine level. Physics constraints are designed to react to bone movement in world space, so moving at the skeleton level rather than through a bone hierarchy can help avoid unintended physics reactions. As noted regarding flipping characters: "Instead of changing the scale of the skeleton, it would be better to flip the character by changing the scale of the actor."
Disable physics inheritance via Transform Inheritance
You can disable certain types of transform inheritance on the bones that have physics constraints. For example, unchecking Rotation or Scale on a bone means it won't inherit those transforms from its parent:
Rotation — When unchecked, the bone does not rotate when parent bones are rotated.Scale — When unchecked, the bone does not scale when parent bones are scaled.
This won't completely isolate physics from translation, but it can reduce unwanted physics reactions depending on your setup.
Use Transform Constraints with Mix = 0
Another approach (similar to how the Alien example handles jaw/eye detachment) is to use transform constraints to drive your physics bones independently of the camera bone. When the camera bone moves, the physics bones follow their own transform constraint target instead. Setting the Mix value to 0 on a transform constraint allows the constrained bone to move freely based on its own transforms.
Work at the export/rendering stage
If you're using the camera bone purely for the purpose of compositing exported video, consider applying the camera movement in your video editing software after export, rather than inside Spine. This way the skeleton and physics are not affected at all.
The most robust solution for runtime use is to handle camera movement outside of the Spine skeleton entirely — at the engine or rendering level — so the physics simulation only reacts to actual in-world character movement rather than camera transforms.
