Transform Constraints for Tall/Short items in Unity runtime?

jackni

Hello,

I am working on a game with a complex mix-and-match customization system (using partial skins). I have a very large number of clothing items.

My character has two different body proportions: a "Tall" version and a "Short" version, which share the same base skeleton.

To make the clothing items fit both proportions, I am using Transform Constraints. Some clothing items are designed for the "Tall" character, and others are for the "Short" character, but they can be combined freely.

My core question is about the correct workflow, specifically: When should these Transform Constraints be enabled or disabled?

For example:

Should I control this inside Spine (e.g., keying the constraint's "Mix" value in an animation)?

Or, should I manage this from code in the Unity runtime? (e.g., when the player equips a "Tall" item, I use code to find and enable the corresponding constraint, and disable it when they equip a "Short" item?)

I am not sure what the best practice is for managing this logic between Spine and the Unity runtime. Any advice on the proper workflow would be greatly appreciated!

Thank you.

Misaki

jackni Both approaches are effective, so it really depends on your preference.
One thing to note is that when you have a large number of transform constraints used for different proportions, it can be cumbersome to toggle them on or off via code. Additionally, if you later rename the constraints, you’ll need to update each reference in the code, which can be quite a hassle.

In such cases, I recommend using skins to group the constraints together.
You can create a skin that contains only the constraints related to proportion changes. When this skin is applied together with the skins for appearance, it allows you to build a system where proportions change accordingly.

The example shown in the video above can be downloaded below:

skin-constraints-example.zip

3MB

As for the advantages of modifying transform constraints via code at runtime: if your specification allows for smooth changes within a continuous range—for example, height values from 1 to 100—rather than toggling between two fixed states like “tall” and “short,” then dynamically adjusting the mix value of each transform constraint via code may be preferable.
Skins are convenient, but they have the drawback of not supporting smooth transitions. For instance, if you want to animate the change from a tall state to a short state, using skins can be more difficult.

I hope this helps.