Unit problem in Cloudcompare distance comapre results

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soheilsabz
Posts: 13
Joined: Thu Sep 12, 2019 10:04 pm

Unit problem in Cloudcompare distance comapre results

Post by soheilsabz »

I have two dental stl file which have seems have set the correct units when i opened them in freecad:

Image

The units have set but based of this post it must not be set to specific unit :

> STL files are unit-less, so they don't contain the actual units. Most
> people use mm, as that is what all of the 3D printing slicers seem to
> expect. When you import the file, you can set the units to import in,
> and then the scaling should be correct.

When i changed the unit in freecad to meter also be using the distance tools i get same as before ( when it was on its default as mm!) like this:

Image

so i think it must be have one default data which freecad based of that convert the points distance to new units and dont know how it done/

anyway my problem is the cloudcopmare which based of this post have not any specific unit setting :

> Mesurements are expressed in the same units as your clouds.
> CloudCompare doesn't handle units (what we call 'implicit units').
>
> In your case it looks like it's in millimeters? Or fractions of inches
> maybe?!

Now i have two stl file like this:


Image

which give me this output data like this:

Image



And the question is the c2m distance are based of what? ( mm or 1/x of mm ),
so for example the difference for first point of target stl file with reference is -3.303671 mm or etc unit!?

Do i need to ask about the setting of scanner device or can i found it by myself?

The reference stl file could be downloaded from here and the targets to be compared with it also uploaded here.

I guess it must be mm but not sure and asked here to be clarified.

Also asked here:

https://engineering.stackexchange.com/q ... 3226eadfdf

Thanks.
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