There are two important concepts before you start making your 3D model, if you
tend to 3D print your model. First is the absolute tolerance and then the other
one is the printing resolution. Hi I'm PJ Chen, an authorized Rhino trainer. Let's
talk about the difference between those two and how important is it for 3D
printing. Let's get started.
When we open the new Rhino file, you're going to come up this window and give
you the template. They are two type of the template in all different dimension. Let's
using millimeter as an example, you have "small object millimeter" and you also
have "large object millimeter". what is a major difference? It is right here, on the
right bottom corner, you will see absolute tolerance
and what that means, in those two differences, is the small object mm template
has much smaller tolerance. Let's take a look how it's
different. I already have this model made and let's take a look on our absolute
tolerance if you go to Rhino "options" and then you can go to "unit" right here. You
will see "absolute tolerance is 0.001" unit now I'm going to open another one
Let's do a comparison. This one, I have it pre-open here and let's take a look on
this one. I'm going to set this one for "absolute tolerance is 0.1" so this a
thousand times different compared to the file. Okay, let me minimize this window so
we can do next to comparison next to each other. I'm going to copy this model
and ctrl-c and ctrl-v to bring this model to the other file, which has a
smaller absolute tolerance. If we try to do the model, a lot of time we need to
fillet the edges, so let's take a look on this one. I'm going to go to the 3d the
solid tool, and we're going here for "Fillet Edges". Right here that radius I
want to set it really small 0.01. You can just type it 0.01 here, and we're gonna
pick up this really common mistakes, that happens here, is when you get to something
really pointed and then you use too big of radius. It won't work, so you have
to go smaller so 0.01 if we zoom in we got a really nice fill it there. Now,
let's take a look on this one with the larger tolerance and then we're gonna do
exactly the same things. We're gonna go into the "Solid" and then under the solid
tool you have this "Fillet Edges". So we want to pick up this one and then the
radius we want to study the same 0.01 hit Enter and pick up the edge. All the
sudden you see the huge chunk of the model is disappeared. And both models are
actually exactly the same. Why the one on the left is working, the one on the
right is not working. It's based on the absolute tolerance, because the one on
the right absolutely tolerance is 0.1 and you want
to go smaller than its tolerance to 0.01. That's why it's not working. So let me
"Undo" (Ctrl=Z) this one, and I want to do any size is bigger than 0.1, so that's
do this again. This time, I wanted to use the radius is 0.11
which is a little bit bigger than 0.1, and let's take a look. Now it's working,
so what I mean is if your model is preset in the tolerance, which is larger,
a lot of time when you get into really tiny pointed, in which happen a lot in
the jewelry design, then you will have the problem when you try to fillet the edges,
because the tolerance is too big. You might wonder, PJ, why don't you
set it to 0.00001, so that way you can fillet any kind
of edges, and you have no problem with it. Well, that will increase your file size
dramatically. If you have a super strong computer, yes, you may able to do that but
it's really not necessary. The reason it's not necessary is most of the printer
is going to 0.002, so if you do 0.001 it's
definitely enough for the resolution on most of the jewelry 3D printing printers.
Let's also take a look on how to prepare the STL file for printing, and what kind
of a resolution you look into it. Let's go ahead and turn them into the STL file
by "Export" and then make sure that you select two STL file and I'm going to
save it in three different files for comparison. The first one, I'm going to
save to 0.001 and here is 0.001
and then you just click okay. And I'm going to save the other two. The other
one I want to do 0.002 is my file name and just for the comparison
for easy to remember, which one is which, and the third one I'm going to do
is 0.003 that's my file name and then again 0.003
Okay let's take a look on the file size. We just have the 0.001
which is5440 KB, in 0.003 is 4594
it might not appear to be huge different
but if your model is really complicated, it would make a huge difference. so like
we say earlier, Most of the printer is get into 0.002 so if we're
working with our model and set it for 0.001 it's definitely enough
but when you export it you don't have to do anything smaller than 0.002
because that's what machine can takes. Even though you use
0.001 because the printing resolution on the printer is 0.002
then you will still get the resolution for point 0.002.
Alright, so let's take a look on the different adjustment for 3D printing.
A lot of time, I will just "Export select" but if you are really specific in the
certain way, you can turn them into the mesh first. The "Mesh" is living under
icon over here. Or you can go into the drop-down menu and then you can find the
mesh, so now let's get under mesh icon and then we click on our object and then
we come in here. Most of the time, you will see the "simple control". so you can
getting into the "few polygons" or "more polygons" (options) and which I usually will do
just "more polygons" and then you can kind of preview it.
It would kind of mash them into the little
squares for you. If you do like it, you can also use the "detail control" and in the
"detail control" I won't suggest you to play with multiple numbers in
multiple areas, but let's get a really quick understanding for what they are.
I'm going to turning everything into the zero and then right here in the "density"
On the first one you have an option between any number below 1, so let's
try 0.1 and we hit "preview" as you can see the density is a lot looser and
then you can see is you have this point to point become the straight line instead
of curve, so the model you're going to print it out it's going to be really
faceted. Now if we turn it back to one and we hit "preview" then you can see it's a
lot more denser, then you say PJ can you go up to 10. Let's try it and then
we want to preview and then you will go back to the number "1", so the density is
go for any number from the below 1. The maximum angle is you can create make
sure that each of the angle it cannot be larger than a certain angle. Couple
other things you might able to change, for example, you wanna change the minimum
and maximum edge length. That means in this little square- that is the length that
you wanted to do for the minimum and maximum. so that's what that mean. One of
the interesting things is maximum distance edge to surface what that mean is...
I have a draft here for you. Let's take a look on this draft. Let's say, if I am
going to having this circle, and I'm going to turn them into the mesh.
Alright, now the red color here is representing the mesh and then when you
have a straight line across point to point to represent certain curve and
from that point (the tip of the where the two straight line meet) to the surface
original surface that's a distant there, which is this blue line there, and that
is what that mean over there. so that blue line (let's go back to the mesh)
again it's represent max distance edge to the surface so you can adjust that as well
so let's say I'm going to turn everything into the zero and I'm going
to type it 0.1 and let's take a look. so that will be the distance that
tiny little distance from the edge from this point to the tip of the curve.
Alright, so a lot of time, to save my time I will use the "simple control" and I
use more polygons and then that way I can preview my mesh. Most of the time
what I do on my model is first I check it has no naked edge. You go to
"Analyze" then you go to the "Edge tool" then you will see "Show Edge" then you click on
the object you are going to 3D print and right here on the command bar, it will say it
found certain numbers of the edge and there's no naked edges then you are
good to go. So right after that I will use "Export"
then I will choose where it's located and giving the file name, let's say PJ,
and then when you hit "Save", it will ask you like what is "the maximum distance
between the original surface for the solid and the polygon mesh create for this STL
file". right here you need to type in 0.002
and that will be good for the mesh and then you just click okay and that will
be the STL file you send it for 3D printing. Thank you for watching, and I
hope you enjoy the video. Please leave the comment let me know if you have any
questions or any other video you like to see. I'll see you next Monday