How heavy are physics constraints in Spine? (Performance in Unity builds)

slomun

Hi everyone,

I’m currently learning Spine 2D and wanted to understand how physics constraints affect performance and memory usage, especially when exporting to Unity.

I have a few specific questions:

How much runtime cost do physics constraints add compared to manual key animation?

Is the performance difference noticeable on mobile targets?

Are there recommended optimization practices (e.g., limiting bone count, using physics selectively, etc.)?

I read that physics runs on the CPU at runtime, but I’d like to know if anyone has actual benchmarks or profiling data.

Thanks in advance for any insights! 🙏

Spinebot

Physics constraints in Spine are not very costly performance-wise and are roughly comparable to other Spine constraints. They are computed on the CPU, but they are not typically a bottleneck. The performance impact of physics constraints is generally minimal, even on mobile targets, unless you have a very high number of skeletons or constraints. For optimization, it's recommended to limit the number of bones and constraints, use physics selectively, and avoid excessive clipping and vertex transforms. Actual performance should be tested on your target devices, as it can vary based on the specific use case and hardware.