# Blender 3D: Noob to Pro/More Mesh Editing Techniques

|previous=Normals and Shading
}}
```
You previously scratched the surface of
the tools that Blender provides for editing meshes. This page will
introduce more of them.

## Adding More Mesh Pieces

Start with the default cube again. Select it and
 into Edit mode. Press
 to bring up the Add menu.
Instead of all the submenus with all the objects you could add in Object
mode, you will see only a single menu containing only mesh objects.
Select another cube, and use  to move
it away from the first cube.

If you  into Object mode, you will see
that the two cubes look like separate, disconnected objects, but they
are in fact one object, and cannot be selected separately in Object
mode. You can  back into Edit mode, and
make connections between the vertices of the two cubes, which you cannot
do with separate objects. Therefore:


## Linked Selections

If you have some part of a mesh selected, pressing
 will select all other parts of
the mesh that are connected to the already-selected parts. In the above
case of the object made up of two disconnected cubes, you can
 on a single vertex of one cube, then
use  to select all the rest of
that cube but not the other.

Another way to do linked selections is to simply move the mouse over
some part of the piece you want to select, and press
 to immediately select everything
connected to that. Conversely, 
will *un*select everything connected to the vertex under the mouse.

## Separating and Joining Meshes

You can separate a part of a mesh into its own object. The part you are
separating doesn't have to be disconnected from the rest of the mesh.
Simply select the part you want to separate in Edit mode, and press
, and in the menu that appears, choose
"Selection". You will see the selected part immediately change to a
reddish-orange highlight, indicating it is part of the object selection
but not the active object.

Conversely, you can join two or more mesh objects into one. Select all
the desired objects in Object mode, and press
, and you will see them all
immediately take on the orange-yellow highlight indicating they are
*all* the active object.  into Edit
mode, and you can confirm all are editable as part of the same mesh
object.

## Proper Extrusion

You previously discovered how to add whole new sections to a mesh with
. Blender also has a proper
 function, which lets you do
this with a bit more control.

Start with the default cube, as usual. Go into Edit mode. Select just
the top four vertices. Press  to start
extruding, and move the mouse roughly along the direction of the Z-axis.
You will find yourself dragging out a whole new face formed from four
new vertices connected to the ones you previously selected. You will
notice also that the movement of the newly-added part of the mesh is
automatically constrained to be parallel to the Z-axis. Press
 or 
to finish the extrusion operation.

Deselect everything. Now try selecting another four vertices of the
original cube, say making up a face pointing along the X-axis. Now if
you extrude these, you will see that the extrusion is automatically
constrained to move only parallel to the X-axis.

A quirk of the extrusion function is that if you press
 and then immediately abort with
 or ,
*the additional mesh piece is still created*, but it is left in the same
position as the original mesh. To *really* abort the extrusion, you have
to undo it with .

### More Extrusion Options

brings up the Extrude menu, which gives you access to more options,
depending on what you have selected:

-   "Region"---extrude the entire selected area as one, exactly
    equivalent to .
-   "Individual Faces"---if you have more than one face selected, then
    they are extruded separately. In particular, any edge common to two
    selected faces will give rise to two separate extruded edges, rather
    than one.
-   "Edges Only"---extrudes only the edges; new faces are created only
    connecting the new edges to the existing ones, not between the new
    edges.
-   "Vertices Only"---extrudes only the vertices; edges are created only
    connecting the new vertices to the existing ones, not between the
    new vertices, and no new faces are created.

## Edge Loop Selection

*Edge loops* are an important concept when
constructing meshes. They are so important that Blender provides a
shortcut for selecting an entire edge loop with one click:
 on an edge or vertex that is part
of the loop you want to select, and it will select the entire loop.
Alternatively,  adds an edge
loop to the selection; or, if the part you click on is already selected,
it will *deselect* the entire loop.

For example, try experimenting with a UV sphere: every line of
"latitude" and "longitude" in this mesh is an edge loop.

## Loop Cuts

Sometimes you need to add more vertices to the interior part of a mesh,
perhaps to flesh in some detail. The loop cut function lets you add more
edge loops between existing ones.

Ensure you are in Edit mode. It doesn't matter what parts of the mesh
are currently selected. Press  to
activate the  function. You
will see a magenta-coloured loop wrap itself around different parts of
the mesh as you move the mouse. You can press
 or  to
abandon the operation at this point, or once you see the loop appearing
around the correct part of the mesh, you can use
 or 
to proceed. Now the magenta colour changes to the usual orange-yellow
selection highlight, and will now restrict itself to sliding along this
section of the mesh as you move the mouse. If you press
 or 
at this point, you will end up with a new loop of vertices and edges at
the last-shown point, while  or
 will still create the new loop, but
leave it positioned at the midpoint.

When the loop is still at the magenta stage, you can use the mouse wheel
to increase the number of cuts to 2 or more. You can also type a number
of cuts using  \...
.

## Edge Loop Deletion

Conversely, you can get rid of edge loops as well, reducing the
complexity of the surface without leaving holes in it. Select the edge
loop (the quick way is  on a
component edge or vertex as described above), then bring up the deletion
menu ( or
) and select "Edge Loop". The selected
loop will disappear, and adjacent edges and faces will be merged.

## Subdividing Parts

A loop cut always cuts a complete loop. Alternatively, you can
 just a selected part of the
mesh: make your selection, then press 
to bring up the Vertex Specials menu, and select the top option,
"Subdivide". This will create one cut, but a panel will appear at the
lower left of the Toolshelf ( to make
it visible at the left of the 3D view if it's not), where you can alter
the number of cuts and other settings. This same option is also
available on Edge Specials .

Another option is the second one on the
 menu: "Subdivide Smooth". This one
computes a
Catmull-Clark
interpolation to give more of a curve rather than a flat subdivision.

## Subdivision Surface Modifier

A  causes some change to the
geometry of an object just before it gets rendered. The change does not
affect the object as you view and edit it in the 3D view, or as it is
stored in the document (unless you
 the modifier, which makes the
change permanent). This allows you to create some complicated effects at
render time, while the original mesh stays simple and easy to edit.
Modifiers for the active object are applied and controlled in the
Modifiers
![](Blender255ObjectModifiersContextButton.png "Blender255ObjectModifiersContextButton.png")
tab in the Properties window.

![](Blender263ModifiersMenuSubsurf.png "Blender263ModifiersMenuSubsurf.png"){width="400"}
A  (also
known as a "subsurf" modifier) applies the Catmull-Clark interpolation
discussed above as a modifier. Being a modifier, it applies to the
entire object, not just to selected vertices. But since the original
mesh is preserved, you use it as a *control cage* to adjust the shape of
the interpolated curve. 
![](Blender263SubsurfModifierSettings.png "Blender263SubsurfModifierSettings.png")
Start with the default cube selected in Object mode, as usual. Go to the
Modifiers tab in Properties
![](Blender269PropertiesIcon.png "Blender269PropertiesIcon.png"). When
you select "Subdivision Surface" from the "Add Modifier" menu, a new
panel appears as at right. Notice the two value sliders under the
"Subdivisions" heading; \'View\' controls the level of subdivision
within the 3D view, while \'Render\' applies to the actual render; the
higher the number of levels, the closer to a curve the interpolated
geometry becomes. Having two separate settings for working environment
and render allows for faster operation in the 3D view, with the usual
tradeoff of lower quality, while still allowing maximum quality for the
final render.
`{{B3D:N2P/Note|'''Keyboard shortcuts:''' Because the Subdivision Surface modifier is so heavily used, there is a set of hotkeys for adding the modifier to the current object if it doesn’t already have one, and setting the number of subdivision levels in the 3D view: {{B3D:N2P/Do|CTRL|1KEY}} .. {{B3D:N2P/Do|CTRL|5KEY}} for setting the view levels to 1 .. 5 respectively.
}}`{=mediawiki} 
![](Blender263SubsurfedCubeObjectMode.png "Blender263SubsurfedCubeObjectMode.png"){width="120"}
As soon as you add the modifier, the appearance of the cube should
change to look something like at right (here shown with just one level
of subdivision). 

The upper part of the panel (from the "Apply" and "Copy" buttons
upwards) is common to all modifiers. Note the X button at the right.
Clicking it gets rid of the modifier. Notice also a group of 4 icon
buttons in the middle, the leftmost two look like a camera and an eye.
The icons are defined as follows (from left to right):

-   Use the modifier during rendering
-   Show the modifier effect in the 3D view
-   Show the modifier effect in the 3D view in Edit mode (if this is
    unchecked and the previous one is checked, the modifier effect
    disappears while in Edit mode)
-   Show the mesh as though the modifier were applied to it in Edit
    mode.

Unchecking the first one lets you disable the modifier without losing
its settings. The remaining three can be handy if you're trying to
disentangle the effects of different modifiers during editing.

![](Blender263SubsurfedCubeEditMode.png "Blender263SubsurfedCubeEditMode.png"){width="120"}
When the third button is enabled, the mesh will look like this in Edit
mode. The original mesh remains highlightable and editable. A preview of
the effect of the modifier is also visible, and responds immediately to
any changes made to the original mesh. (Try moving some vertices around,
and see what happens.) 

![](Blender263SubsurfedCubeEditModeApplied.png "Blender263SubsurfedCubeEditModeApplied.png"){width="120"}
The fourth button goes one step further and acts as if the modifier has
already been applied, while allowing you to edit only those parts
corresponding to the original mesh. (This button affects the behavior of
the third button. It cannot be used independently, and may disappear if
the third button is unchecked.) 

## Sharpening the Curves

The subdivision surface modifier offers much more control over the
resulting shape than might be apparent from above. For example, you may
not want uniform curvature everywhere, you may want some parts of the
shape to have sharper edges. This can be achieved in two ways:

-   by applying a *crease* value to selected edges
-   by strategic positioning of additional vertices in the control-cage
    mesh.

### Applying a Crease

![](Blender267SubsurfedCubeCreasedEdges.png "Blender267SubsurfedCubeCreasedEdges.png"){width="160"}
Select the edges where you want the curve to be sharper. Press
. Note how the curve gets pulled
more or less closer to those edges as you move the mouse. The selected
edges take on a magenta colour, indicating they have a nonzero crease
value applied.

The crease value can be seen and edited in the Transform panel at the
top of the Properties Shelf at the side of the 3D view (you can toggle
its visibility with . Values can range
from 0.0 (no crease, the default) to 1.0 (maximum sharpness of the
edge).

### Adding Vertices

![](Blender263SubsurfedCubeLoopCut1.png "Blender263SubsurfedCubeLoopCut1.png"){width="160"}
For example, start with the subdivided cube example as above. Press
 to start a loop cut, and position
the magenta outline something like this: 
![](Blender263SubsurfedCubeLoopCut2.png "Blender263SubsurfedCubeLoopCut2.png"){width="160"}
Press  or
 \... 
![](Blender263SubsurfedCubeLoopCut3.png "Blender263SubsurfedCubeLoopCut3.png"){width="160"}
\... and move the mouse so the newly-added loop moves closer to one side
of the cube. See how the subdivided mesh develops a sharper curve on
this side?

To confirm the placement of the new loop, press
 or .


### Which to Use?

The basic principle is, the closer together the vertices are, the more
control you have over the curve at that point. So the question is, do
you just want a sharper edge, or do you want more detail? That will
govern whether you need to add vertices, or just apply a crease to the
existing edges.

