Some help with shiny bits

Discussions Metro Series
1

I’m using a MetroX to scan the fingerboard of acoustic guitars. They tend to be black, with shiny frets, which I know is very unfriendly. Here is the setup. I’ve scanned about 100mm of the fretboard, then export the mesh to MeshLab and create a slice through a fret, along the green line in the image.

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f11328×1058 202 KB

From inspection under magnification I know that the frets have nice smooth rounded tops. Here is an example of the profile I’m getting for a fret:

f2
f22626×1144 162 KB

Not only a lot of scatter in these four scans, but an unrealistic trough in the middle of the fret. Scanning spray is an obvious thing to try, but these guitars are expensive (10x the cost of the scanner) and have various types of finishes, some of which aren’t known. So I’m reluctant to use spray. I might be able to mask all the frets, but that’ll be a PITA.

I’ve tried -

  • using defaults for exposure, brightness, fusion, meshing
  • Cross lines, parallel lines
  • General, Black, Shiny Metal
  • Increased laser brightness, varied exposure

Any other suggestions would be appreciated. Maybe the technique for scanning (fast, slow, lines diagonal to frets…)?

TIA

2

Hi! I guess removing the strings would greatly help :sweat_smile:

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3

Remember to capture at least 10.000 frames when using laser mode cross line to get the smooth surface and as @ivan already stated , remove the strings

Try to fuse it at slightly higher settings like 0.2

Don’t use 3D spray on music instruments

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4

The goal is to use the scanner to measure the shape of the neck moving from the nut to the bridge. That has to be done when the neck is under string tension.

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5

Thanks. I’ll give that a try.

6

I believe I found the solution to my scanning problem. In case it’s of any use to the dev team, or to future readers, I found that the problem goes away if I hold the scanner at an oblique angle to the frets. Previously, I was holding the scanner looking straight down onto the fretboard for a good part of the scan. If I always keep it at an angle, e.g. off to the side, the troughs in the fret tops disappear, all is great, and the scans agree well with measurements with a micrometer (green circle). This is quite repeatable so I’m sure that was the cause. Must have to do with reflections on the fret tops or something.

This is what I get now, from 5 separate scans-

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f1a3130×1296 224 KB

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7

You always have to hold the scanner at 46 degrees while scanning for best results , direct scanning at 90 degrees will miss too many data, glad you found it out by yourself :+1:t3:

8

Thanks. Where is the best place to learn any other good practices for scanning with the MetroX? I didn’t see any mention of holding at 45° in the user manual.

9

Here the official ones. Check the Playlist section, there are three about metro X.

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10

Check the official channel that @Ivan just posted , also check the tutorial section of the forum here .

You may not find everything in the official manual , but I scan already for 30 years and over 3 years with Revo point scanners .. so see it as a good tip from the community and use it .

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