1 Topic by fhenryco

  • fhenryco
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Topic: light conditions and other questions

Hi everybody,

i'v just assembled and done my first scans with atlas3d. My simple questions surely have been asked somewhere else here but at first glance at the topics i dont see them...

I need to scan an uniformly white plaster object which i actually obtained by moudling my own finger. it's not high because it's only one phalange, yet it's probably already too high so the scanner cuts the summit (a hole in the region badly accessible to the laser: grazing angle) .

My questions are:

- What are the best light conditions for such object (daylight?, obscure room? )
- any other advice for the settings in HD?
- I'm going to lower the object as much as possible, but if there is still this hole, what is the solution to get a complete scan? is it possible to scan the object twice in two different positions and then merge the two scans by software? any good tutorial around to get that ? i have meshlab installed

Thank you in advance for helpul advices and comments

Fred

2 Reply by Mwaypilot

  • Mwaypilot
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Re: light conditions and other questions

Re the multi scan question
Do a search on here for user (pirvan) he has done a couple of good write up the second one is about multiple scans
Bill

D4S + S3d 18 months and still learning
Filastruder

3 Reply by pirvan

  • pirvan
  • pirvan
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Re: light conditions and other questions

When you have reflective object, or one on which the laser washes out, the best thing to do is coat the surface with something that will reduce the reflections. 

Some folks had gone to the extents of painting the model with a flat primer, but that's pretty drastic.  Instead, I "borrowed" some make up powder from my wife, and mixed with some talcum (baby) powder, and I use a makeup brush to apply the mix to the model. 

It doesn't need a lot, just enough to lightly coat the surface.  This works wonders, and when done, you simply blow the powder off your model.

To print or, 3D print, that is the question...
SD3 printer w/too many mods,  Printrbot Simple Maker Ed.,  FormLabs Form 1+
AnyCubic Photon, Shining 3D EinScan-S & Atlas 3D scanners...
...and too much time on my hands.

4 Reply by fhenryco

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Re: light conditions and other questions

I have another more theoretical question: i dont understand why two lasers are needed, since given the symetry of the table both lasers should have seen exactly the same scene after 360°.  It would have made more sense to have a second laser looking at the scene from above to really catch points from a different angle and allow the lasers correct the grazing angle effects from one another...

5 Reply by ephestione

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Re: light conditions and other questions

Actually, it would have been useful to have a second camera rather than a laser on a different position: if the laser line is out of the camera's reach you won't be able to see the detail in the scan. Also, if you think about it, being the lasers on a parallax of the camera, they can point different details that might not be visible when the model rotates to the other side.

6 Reply by fhenryco

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Re: light conditions and other questions

as i eventually figured it out , it's usefull to have those two lasers for those faces of the object which normal deviates much from radial direction yet remaining in the plane of the table.

This is why for an almost isotropic object in the plane of the table: cylindrical symmetry  (as the one i'm scanning) it does not matter to use the two lasers.