Now I want to go
over how to do
some manual editing and
cleaning in Meshlab
with the selection tools.
So a lot of times when
you get a raw mesh,
especially from a CT scan,
you'll get some
isolated faces floating
or artifacts like what
you can see here.
And actually I'll
turn on the edge
highlighter so you
can see this a little
better. Where
you've got kind
of these little
faces sticking
up from the main
part of the mesh.
And then these
bridges that are
kind of connecting to
parts of the mesh.
And these are not
only going to cause
issues for things
where you need a watertight
mesh like 3D printing,
but they're also
going to be a problem
for measurements
like surface area,
where having lots of
these little artifacts
or isolated
faces sticking out
are going to increase
your surface
area measurement
and inflate it beyond
what you would
have for a mesh
that didn't have any
of these artifacts.
So the first thing I
start with when I'm
working with a mesh that's
directly generated
from a CT scan
is to get rid of
any isolated faces.
So to do this
in Meshlab,
we can use the connected
components selection tool,
which is found right here.
And basically this will
just select all of
the faces that are
connected to each
other from where you select.
So all I have to do is drag
the little box right over
the main rodent jaw
mesh that I
want to select.
And now you can see
it's entirely selected.
If I turn off
the selection,
I can rotate around
and view and it looks like,
yeah, it got
everything selected.
>> But if I go inside,
it can be hard to
see right now,
but there's
actually a couple of
little floating pieces
that are unselected that
I'm going to want to delete.
>> So if I go
back into that
connected components
selection tool,
you'll see that
it pops up with
this little tab that has
the controls for you
to know right away.
And so I can just
click I to invert
the selection.
And now my main rodent
jaw is unselected,
but all those
little faces are.
And I can actually
go back in there
and we should be able
to see them right there.
>> So now I can just
delete those by
hitting this
delete button.
And out of the three
delete options,
this is the one you
want because it
will get rid of
both the vertices
and faces,
and not just one
or the other.
Ok, so now those
isolated faces are
gone and we can
start dealing with
these other artifacts
on the surface here.
>> Okay, I want
to get rid of
this little bridge thing
that's coming up with
this edge right here.
And I can do that with
the polyline
selection tool.
So that's this
button right here.
And again, the
instructions come up,
so you can always
refer back to these.
But basically all
you do is click
around the area you
want to select.
And then click
the Q button
to add this area
to the selection.
>> Now if I exit the
selection tools
and rotate around,
you'll see that
not only did
select through to the
other side of the face,
this here, but it
actually selected
through the entire mesh.
So we're going to
want to unselect
these before
deleting the part of
the mesh that we
actually want to delete.
And I do this by
rotating to a different
viewpoint where I'm
going to only be selecting
the faces that I don't
want to delete and not the
ones that I do want to
keep in selection.
So I'll just hop back
in that polyline tool,
select around this region,
and then click W to
subtract it from
the selection.
Hop out again,
go over to this other side
and again use the
polyline tool to
subtract it from
the selection.
>> So now if I do a
quick rotate around,
I can see that it's
only this little
bridge artifact
that's coming up.
And again, I can just
hit the delete button.
And now you
can see I have
deleted those faces
that were coming up.
>> The other selection
tool you can
use is just a
rectangular selection.
And I really
find this useful
only if I'm trying to
select individual faces,
because this allows
you to select
only what's visible and
won't select through
the entire mesh.
So I want to get rid of
this little face
that's sticking up
here so I can
close this hole.
So if I hold down Alt,
it should only selects
what's visible, there we go.
So I hold down Alt and
it's only selecting
what's visible.
So then I can go and
hold down shift to
subtract these
extra little faces
that got selected.
And again, just to be safe,
I'm going to check and
make sure I'm only
selecting what I want
to be selecting.
But it looks like
that is the case.
>> So I click delete and
now this is a hole that I
should actually
be able to fill.
So Mesh Lab has
this filter called
close holes,
and you can
either run it to
apply over the entire mesh,
searching for any holes of
a given size or
smaller to close.
Or you can just do
it on selected faces.
>> So I'm just going
to test it out like
this and see if it'll
catch that hole
that I have.
And it looks
like since I still
have some geometry errors,
it's not going to
work that way.
So I'll probably have to go
through and clean
this up quite a
bit more before
I can really
start filling the holes.
