We need to find a way to hollow out this solid box.
And to do this, we're going to use the Shell feature.
We're going to open the enclosure parent part
directly now in order to edit it.
Often in solid works, it's just a little bit faster
to open the part in editor instead of editing
within the assembly.
So to do this, all we need to do is select the part
either in the parts tree or in the graphics area
and then click on Open part, which is the first icon here.
So now we're directly editing the enclosure parent part.
Over here on the left, you can see we've got
the main shape extruded feature.
You can see next to it we've got this small arrow
and that indicates that this feature
has an external reference, and that means that this feature
is linked to another part.
In this case, that's the PCB part.
To hollow out this block is pretty simple really,
all we need to do is use one feature.
So let's go to the Features tab
and then select the Shell Tool, which is this one.
You might remember that we set the walls
were going to be three millimeters thick,
so make sure you have three millimeters written in up here
and you might have to show preview box selected.
If so, you should be able to see this yellow preview.
Often I tend to turn this off because if you've got quite
a complex model, it can take a little while
to generate that preview.
But in this case it's quite simple,
so it's okay to use that.
So let's press Okay to add that feature.
So now you can see down here we have the Shell feature
in the feature tree.
If you spin your model around,
it doesn't really look any different.
If we go to a cross-section view by clicking on this icon
and we drag through the model,
we can see that it's now hollow
and has three millimeter thick walls.
We've made them three millimeters thick for this print
but it's really up to you.
I'd recommend using two as a minimum,
you can probably get away with one
if you have a really decent printer
and your model isn't very big.
But by using three here,
it just gives us plenty of space
to add more features later on.
So let's close that cross-section view
and now we can go back to our assembly.
If you press Control + Tab together, you can cycle
through your open documents
and we can use that to go back to the assembly.
So now if we go to another cross-section view,
we can drag all the way through the model
and we can see that the box is now hollow
and that the PCB fits inside it.
So again you can close that cross-section view
and then you can just press Control + S
and save your assembly.