How to measure the angle of curve from a real object?

I have print knife handle before and I just draw the outlined onto white paper and capture it with camera, after that I draw it with photoshop to make the lines more clear, next step imported the image into Freecad and just make the model from the picture and that does not really have an exact curve, but still acceptable.I know a little about design model in Freecad and Fusion360 and sometimes I curious how you all measure the angle of a curve from a real object? Did you need a 3d scanner or what?It would be a great skill for 3d printer hobbyist like me. Sorry if my English is not clear. I am not a native English speaker.

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This is a very good question! I try not to duplicate anything with curve for this reason. The one time I did do this, I was making a sheath for a knife and just held the knife up to the monitor with the model sized as the knife.. Obviously this would not work with most objects.. Interested to hear what others do!

If you have a curve,I duplicate real life objects all the time to print them as replacement parts, I used to find this difficult but if you think about how a curve is made up, it's not very difficult, there's a line leading up to it and a line exiting it, if you know the difference and have the lines placed where they belong, then just add in the curve. That usually does it for me, sometimes figuring out how many segments in the circle can be tricky, but generally you can tell if it's a very smooth (high segment) or kind of blocky (low segments).That's usually how I do it and that works for me, hopefully that makes some sense.

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Originally Posted by airscapes

This is a very good question! I try not to duplicate anything with curve for this reason. The one time I did do this, I was making a sheath for a knife and just held the knife up to the monitor with the model sized as the knife.. Obviously this would not work with most objects.. Interested to hear what others do!

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yep that's pretty much how i do it as well. hold it up to the monitor :-)

works surprisingly well.

I've never tried that .Perhaps I should.

I also have an angle finding widget.(lightbulb moment)
it's called a protractor ! (lol)
https://www.amazon.co.uk/Helix-Oxfor...5189974&sr=8-5

between that and using the monitor you should be able to match and replicate most curves :-)