I am struggling for a couple of days to measure length of the curve. I tried several addons and solutions but nothing worked for me properly.

Basic idea is that I would like to measure circumference of the tshirt. First I have created a plane, then put it where I would like to take a measurement intersecting with tshirt. I used bool intersection in order to create object which I would like to measure. Next after highlighting it I converted it to curve. Now I am trying to take a measurement but I do not know how.

Here, I create an empty object which takes your curve as an input, measures the curve length and creates a line whose length is equal to the curve length.

You can now, for example, use this objectâ€™s z-dimension in a driver if you need the curve length elsewhere. curve_length.blend (3.7 MB)

You could even convert an intersection procedurally to a curve and measure itâ€™s length: