Hi, my name is Swann with the 3D scanning
company Holocreators. Today I will show you how to do a 3D scan
for free using just your cell phone camera. The technology is called photogrammetry. It has been covered by many video tutorials,
but I think whether you are a novice or an experienced user, I will show you something
new today, because I am not only making the 3D scan for free, I will also make the 3D
scan with a professional scanner which costs around 20,000 Euros and later on I will compare
the two. And just a little heads up, the deviation
between the two is just 0.2mm. So, what we get for free is actually pretty
damn good. To follow this tutorial you will need—well,
apart from a cell phone camera—four free software packages. You will need Meshroom. That’s for converting the pictures you have
taken into a 3D model. We will need MeshLab. That’s for 3D scan cleanup and alignment
of the different 3D scans. Then you will need Netfabb. That’s for taking measurements on the file. And then finally we will need GOM Inspect. This is for comparing the free scan with the
professional scan. So the very first step is to actually make
a manual measurement. So for that I will take this caliper here
and I will take a measurement on the flange. If you don’t have a caliper you might as
well take a ruler. Then I will take 3 separate measurements. That is just to get an average. And then you will see that the measurement
is 76.2 mm. And this is our reference measurement which
will get very important down the road. Now we start the actual scan. I will place the part on this yellow box and
then I’m taking my cell phone camera and I’m moving around the box taking many pictures
from different angles and perspectives. While making these pictures I pay attention
to have a very good lighting. Actually the more light the better, but you
don’t want to have harsh shadows on the object. I will make two picture sets of around 100
pictures each. One is where the part is sitting on the flange
and one where it’s upside down. That is because I also want to record the
inside geometry of this part. Now it’s time for Meshroom. We import the pictures that we just made with
camera. That’s super easy. Just by dragging and dropping. And then you see the start button. You hit that and the software will calculate
the 3D models from this picture. We do this two times. Once from the picture set that we made from
the part sitting on the flange and once where it’s upside down. So in the end we have two 3D models created. The two 3D scans which I have created in Meshroom
I will now import one by one into MeshLab, and here I will remove everything that is
not really needed in the scan. Because Meshroom has, well, apart from the
part, it has also recorded some parts of the box, and these areas we want to remove. To remove areas of the 3D scan I can click
up here on the button select faces in a rectangular region and now I have this red
selection box and I select it in red and then I hit the delete key and this is how I can
remove geometry. And when I am happy with the result I can
just export it as an STL file. I think I’ve said it before. Photogrammetry is a great technology, but
one major disadvantage is that it’s not according to scaling because you have a picture
set and the computer calculates a 3D model from it but it doesn’t know how big the
part is in reality. For that we now check the scaling of the 3D
scan. I will import the 3D scan to NetFabb, and here I make a new measurement and then
I select 3 points on the outside of the flange and then NetFabb supplies me with the correct
measurement which in this case is 6.98mm, and now I click on scale, we make a quick
calculation. You remember the reference measurement that
we have taken that is 76.2mm, we divide that by the measurement we just did which is 6.98mm,
and then we get the scaling factor of 10.917. And the scaling factor we put in here, and
then we hit scale, and then you can see how the 3D model is scaled up. And again we export the file as a STL file
from NetFabb. The final step for the actual scan is to combine
both 3D scans—the one sitting on the flange and the one upside down. For that, again, we use MeshLab, one by one
we drag and drop them into the software. And you can see them now inside the software. And now we hit the yellow button up here with
an A. And on the right side here we have the two scans. We select the upper 3D scan and click on glue
mesh here. And then we select the lower 3D scan and click
on point based gluing. And now this new window opens. And now we try to find distinctive features
which are similar in both scans, because we are helping the computer to align both. This is by selecting points with numbers. You should at least select three points. And now we click on OK and the rough alignment
has been done. And now when we hit process the detailed alignment
will begin and also the computer will supply us with a global alignment error which in
this case is 0.001 which is really good. The final step we again select the parts that
we don’t really need, the upper and lower part, and hit the delete key, and now our
scan is finished. The final step is to select both scans and
flatten visible layers. And now we can export the 3D scan as a STL
file. I told you that I also 3D scanned this part
with a professional scanner. So now I want to show you the comparison between
the two. In this animation, first you can see in yellow
rotating our 3D scan, and then afterwards in green you can see the professional scan
that we did. This scan was made with the 3D scanner Artec
Space Spider, a professional scanner which costs about 20,000 Euros. It’s a little cleaner. But you could expect that from a professional
device. Now let’s check how accurate the free 3D
scan actually is in comparison to the professional scan. For that we will use the software GOM Inspect. Again drag and drop both 3D scans into the
software. The free one and the professional one. Then we hit automatic pre-alignment. On the right side you can now see an explanation. It’s a gradient going from red over green
to blue. And, well. If it’s green that means there’s no deviation
between our free scan and the professional scan. If it’s red that means there’s material
from the free scan above the professional scan, and in the blue area, it’s the other
way around. We also want to see in selected places the
deviation and for that we can set deviation labels. These are like markers showing us in selected
areas the deviation between the two scans. And here you can see that the deviation is
about 0.2 mm between both scans on average. I will supply all files on our blog to download
them – the free scan, the professional scan, and also the report that that compares the
two. On a final note. Holocreators, my company, is a 3D scanning
company. So we do 3D scans with photogrammetry, structured
light, and even computed tomography—that’s XRay scanning—and you get really accurate
scans with that. So the accuracy range that we offer goes from
0.1 mm down to 0.005 mm so we make highly accurate scans. So if you have a project where you need that
kind of accuracy, please get in touch with us. Now that we have created a 3D scan for free,
for many of you that might just be a first step in a long process of working with these
files. Many of you may want to convert these STL
files into a STEP files. For this I have also prepared a tutorial called
STL to STEP and in that I will show you how to use free software to convert STL to STEP
files.
That was VERY cool!
3D scanning always depends on the end purpose. The end purpose isn't to manufacture a broken flange, but reconstructing the circular mount wouldn't be that difficult. Yeah, the mesh merge in Meshlab is powerful. The end purpose of this would be to make it 3D printer ready and then 3D print it in stainless steel, so the replacement part is superior to the broken, and probably unavailable, part.