: How To Find Out Exact Angle Measurements of Object in Photo Hi Folks: I am having a guitar body built and I am having no little trouble illustrating certain changes I'd like to see made.

@Caterina889

If you have the guitar you are trying to copy, can't you at least lay the guitar on a sheet of paper and trace the outline of the body and send that to the machinist? Seems this would be the best method, short of sending the actual guitar to the machinist. Of course, if all you have is that photo of the original, things are different.



I'm not certain it's possible to extract exact measurements from a photo. You would first need something to reference for scale and there doesn't really appear to be much to meet that requirement in the photo. I suppose you could use the fretboard, given those are a standard width. But that's not really the issue here since I assume you know widths and heights and are more concerned with angles an curves.

You can attempt to get proper angles based on what you see.

Using the Ruler Tool and the Measurement Log (Window > Measurement Log):



With the Ruler Tool and your photo open click-drag along an angle to draw a line, merely eyeballing the angle in the photo. Once you get a line that resembles the angle in the photo click the Record Measurement button on the Measurement Log Panel. That will record data information regarding the line you drew, including the angle of the line in the furthest right column.

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The curves are another matter. I'm not certain Photoshop offers any ability to even guess at curve diameters. You would have to factor in all the various angles then mathematically determine proper curve radii.

Doing this shows the original having roughly a 64° and 129° angle on the right side, where as the CNC piece has roughly 62.5° and 132.5° angles.

(The photos can and will distort angles. The CNC piece isn't photographed straight on, there's an angle in the photo. So, the measurement will be skewed due to that.)

Again, this is all just eyeballing the photo. You might want to measure things multiple times then average those measurements in an attempt to be as accurate as possible.

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@Holmes874

The copied body obviously isn't fully fixable because there's already taken off wood too much. The horns look out too short. If yo want to fix those parts which are still fixable you can make a cardboard model. Scale up the dimensions of your photo (you really should have a better image of the original, it's now too coarse; about 2mm/one image pixel), print it in overlapping parts, glue the parts onto a piece of cardboard and cut the excessive parts off. When handcrafting wood you need something into your hands and under your eyes, onscreen stuff isn't enough.

Start with a test print of a simple shape to see if your printer have some scale error which must be taken into the account. A nearly maximum printable size rectangle with thin stroke is good.

Making the next right: You need proper CAD drawing. You can trace manually the photo in CAD software or in Adobe Illustrator and make a DXF. You surely know some of the dimensions, so the image can be scaled to exact size. From that drawing the CNC guy can make the right program which surely outputs what you have put into the drawing.

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@Angie364

One method would be to superimpose the images over one another to see where there still needs to be adjustments.



However this is faulty since you need to get exact measurements to get anything concrete done. I'd try and look for specs or a large image size of the model you are trying to copy.

If you are set on this method you could use some digital measurement tools like these french curves to measure the edges.

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