- The extrude tool of editable poly,
creates branching structures on a polygon mesh.
We'll use it to add detail to this box,
which is going to be a column,
for the pergola in the courtyard.
The extrude tool is different,
from the similarly named extrude modifier.
Modifier operates on splines.
The extrude tool operates on selected polygon faces,
or edges.
I'll select this column object and go to the modified panel.
And it is a box primitive.
I want to add some segmentation here,
because I need something from which to extrude.
In order to extrude a face,
we need some face from which to extrude.
We can't just sprout a new face from part of another face.
And so I need some segmentation here.
I'll set the number of height segments to three,
and press enter.
And now let's convert this to editable poly.
Right click in the view port,
and from the quad menu, choose convert to,
convert to editable poly.
And now all the tools are available on the modeling ribbon.
I want to move these edges into place.
Let's go into edge sub object mode.
And as we saw previously, we can select an edge loop,
by double clicking on an edge.
Now, get in close with control alt and middle mouse,
select a single edge or double click on an edge,
to select the entire loop.
And we can verify that,
by going into wire frame mode with F3.
We've got that whole edge loop selected,
and I can grab the move tool and I can move that upward.
I actually want to move it to a precise position.
So I'll go down to the transform typing area down here.
And I'll set the Z position for that edge loop,
to 265 centimeters and press enter.
And now that's positioned in place for an extrusion,
of the capital of the pergola column.
Same thing with this other edge loop down here.
I want to move that down.
So I'll double click on one of those edges,
to select the whole loop,
and move them to a Z position of 42 centimeters,
and press enter.
Those edge loops are now in position,
so that I can extrude where I want to.
I'll go into polygon sub object mode,
and I want to select this loop of polygons up here,
at the top or the capital.
There are lots of ways I could do that.
I could select a polygon,
and maybe we'll go into select object modes.
We're not distracted by the move gizmo.
I can add to that selection,
by holding down control and selecting more polygons,
or I could drag a selection rectangle.
And if I'm in crossing mode, which is the default,
then I'll select all the polygons,
that are touched by that selection rectangle.
And we can verify that,
by going back over to shaded mode with F3.
But the easiest way to select that polygon loop,
is with a keyboard shortcut.
So the way to do that is to select a single polygon,
hold down the control key, and double click,
on an immediately adjacent neighboring polygon.
Control double click and boom.
I've selected all the polygons in that loop.
That's a real time saver.
With that polygon selection made, I can do the extrusion.
The extrude tool is found on the polygons panel,
in the ribbon.
It's also available from the modified panel.
If I click on extrude,
then when I hover my mouse over selected polygons,
I get a new cursor.
And click and drag to perform the extrusion,
intuitively there, sort of interactively.
But unfortunately, the result that we're getting,
is nowhere near what we want.
I want those polygons to extrude outward,
along the local normal of the source polygon.
In other words,
perpendicular to the surface of the plane of that polygon.
I'll undo that with control Z.
To extrude along the local normal,
we'll need to go into the extrude options.
And that is done with a keyboard shortcut as well.
Hold down the shift key and click on the extrude button.
And that launches up a user interface element.
This movable little control box called the caddy.
C.A.D.D.Y.
And we have some parameters here.
Most importantly, is the extrusion type.
If I hover my mouse over this top button,
then in the caddy header up here,
we see the word group appear.
So the current extrusion type is group.
Click on that top button and we get a popup menu,
from which we can choose an extrusion type,
and we want local normal.
And now we get the extrusion type that we wanted.
We can just change up the amount,
or the height of the extrusion.
We can set that to, let's say, three centimeters,
and press enter.
And if we have the result that we want,
we can click the check box in the lower left of the caddy.
Click the check box and that executes the command.
There's also the ability to execute multiple extrusions,
one after another, without leaving the tool.
Let's take a look at that.
I'll undo the extrusion that I just made with control Z.
Those polygons are still selected.
Once again, go into the extrude options, hold down shift,
click on the extrude button,
and we get the same options that we had before.
Our parameters haven't changed.
We're extruding by local normal,
at three centimeters of height.
So this time, instead of clicking the check box,
I'll click the plus sign.
And in the header up here,
we see the words, apply and continue.
Click on that plus sign.
What we see here now is a double extrusion,
or what appears to be a double extrusion.
There's really only one extrusion,
that's actually been performed.
What we're seeing is now a preview of another extrusion,
that we could potentially make,
and that is based upon the current selection.
And by default, when we perform an extrusion,
the newly extruded polygons get selected automatically.
And so that's why we appear to see this double extrusion.
But selection, of course, is dynamic.
And if I click on nothing in the view port,
then I see no extrusion.
Click on some polygon like this one here,
and we see a preview of what that extrusion will look like,
when we click the check box.
Okay. I now want to extrude the polygons at the base.
So, I'll deselect that top polygon,
go down to the bottom of my column,
with the middle mouse button,
and select this polygon loop here.
Select one of those polygons. We see an extrusion.
Hold down control, double click on the neighboring polygon.
And we select all those polygons in a loop.
And we see the preview of that extrusion.
Let's make that one a little bit thicker.
We'll make it four centimeters instead of three.
And when we have what we want,
we can click the checkbox that will execute this,
and close the extrude caddy.
If we don't want to perform this extrusion at all,
we could just click the X button here,
and just close the caddy without performing the operation.
In this case, I want to apply by clicking on the checkbox.
And now I've got two extrusions.
One at the top and one at the bottom.
Okay. We can exit out of sub object mode.
And we just performed our two extrusions.
In the next movie, we'll see how to use extrude,
to create depressions rather than extensions.
And we'll add a little bit more detail to our model.