Need help understanding regex functions

this is a continuation of How do I use regex to replace periods in a string?

for context I have a large table with strings containing dimensions

ie. " .175" x 2.5" x 8' "

// " means inches, ' means feet

I need to split every string into columns thickness, width and length. The solution I was provided in the previous example:

let x = "0.75 x 0.75 x 5.25 (144 bar)";

    let numbers = x.match(/(d*.)?d+/g).map(n => parseFloat(n))

    var thickness = numbers[0]
    var width = numbers[1]
    var length = numbers[2]
    //Do the regex function

    const regexFun = () => {
        try {
            console.log(x);
            console.log(thickness, width, length);

        } catch (err) {
            console.log(err.message)
        }
    }

The above will only really work 70% of the time for me due to how some entries are written

ie. " 72" extrusion "

Ideally there is a single line solution out there, but I don’t quite understand how regex works:

/(d*.)?d+/g

In the above how does it return .175 , I would assume it finds a number first and then the dot, so the result would be 175.