How i know how many degrees a bone rotates in his local sapce?

I wanna know for better understand the transformation bone constraint, i never know what values to use, i dont want just guess the values to use. hope u understand my question

The only way I’m able to suggest is by making a dummy driver somewhere, e.g. for a custom property that shows the local angle of the bone (one for each axis).
To get the angle in degrees the script should be:
“var * 180 / pi” , where var is the wanted local rotation of the bone.

would you please show how i do that?

You have to create a custom property for an object (which object and which panel is up to you, it depends on what you want to be visualized during the actions you’ll perform). You do that from “Custom Properties”:

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by right-clicking on the property value you can add a driver:
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then you edit the driver:
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hope it helps.

ok thanks i’ll try it