# Blender 3D: Noob to Pro/Deforming Meshes using the Curve Modifier

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## Understanding the Curve Modifier

The *curve modifier* lets you use a curve shape to deform a mesh. The
mesh will follow every twist and turn of the curve as far as it can
bend, depending on how many vertices it has---clearly, the more vertices
there are, the more faithfully it can follow the curve.

The curve modifier is also very easy to confuse yourself with if you're
not careful in how you set it up. A common situation is you try to move
the deformed object in one direction, but it ends up moving in a
completely different direction! This happens when you choose a
deformation axis that doesn't correspond to the predominant orientation
of the points in the curve.

There are in fact some predictable rules that govern the behaviour of
the curve modifier. Once you understand these rules, you shouldn't need
to keep trying different things at random to try to achieve the effect
you want, you should be able to go straight for it.

### A Simple Example

!Grid plus path objects, ready for
action
Let's do an illustrative example to clarify things. Start a new Blender
document; delete the default cube, and add a grid object instead, with
the default 10×10 subdivision to give it plenty of vertices that can be
deformed. Also add a path curve on top of it---this will give you a
NURBS curve with 5 points, initially in a straight line. The result
should look like at right.

!Grid deformed by path, default
settings
Now  on the grid, go to the Modifiers
Context
![](Blender255ObjectModifiersContextButton.png "Blender255ObjectModifiersContextButton.png")
in the Properties window, and add a new Curve modifier which you will
find in the \"Deform\" column. Click under \"object\" in the empty box
and choose \"NurbsPath\".

The grid object should immediately jump a little way in the direction of
the negative X-axis. Why?

If you select the curve and  into Edit
mode, you should see that, while the origin of the curve's local
coordinate system (the fat orange dot) is in the middle of the curve,
the first point (the one at the end of curve in the same direction that
the "centipede legs" are pointing) has a negative X-coordinate. Select
just that point, and from the Snap menu
, do "Cursor to Selected". Now
 back into Object mode, and from
Object→Transform do "Origin to 3D Cursor". This will adjust the origin
of the curve's local coordinate system to that first point (keeping the
curve itself in the same place), whereupon the grid object should jump
back to its original location.

You can of course freely move around, add and delete the other points.
Just be sure to keep that first point always at the origin of the curve.

![](Blender267DeformModifierSettings.png "Blender267DeformModifierSettings.png")
Now look at the settings for the Curve modifier. Notice those six
buttons under "Deformation Axis:"?

When a path curve is created, all its points initially lie along its
local X-axis. Since the default for the Deformation Axis is "X", all
works pretty much as you expect. If the two do not coincide, then weird
things happen when you try moving things around.

If you *really* want to mess around, you could go into Edit mode on the
curve, select all its points, rotate them to, say, orient them along the
local Y-axis, then get out of Edit mode, select the deformed mesh, and
change the Deformation Axis on its modifier to Y, and things should
still work consistently. But why bother?

As long as you obey the above rules, you can move, rotate and scale the
deforming curve *in object mode only* as much as you like, and the
deformation will still behave in a reasonable fashion. Of course, you
can do what you like to the deformed mesh in object or edit modes, and
this will still be true.

!Fiddling with the deforming
path
Select the curve,  into Edit mode,
select the middle point, and move it a little to one side, as at right.
You should see the grid mesh immediately bend in a corresponding way.

Now  into Object mode, select the mesh,
and move  it around: notice how it
tries to follow the shape of whatever part of the curve lies nearest to
it. What shape does it take when you move it off an end of the curve?
How about to one side?

Alternatively, you can similarly drag the curve instead of the mesh, and
the same thing will happen: it is only their relative positions that
governs the actual deformation.

Also try changing the scaling radius
 and tilt angle
 on particular curve points: note
how the former causes the deformed mesh to get wider and narrow at those
points, while the latter makes it tilt from side to side.

## Another Example

### Setting up your Mesh

While this example will be done with a cone primitive, you can use the
default cube or another shape of your choosing so long as it can be loop
subdivided along the axis you wish to curve. Delete the default cube if
you\'re not going to use it as your base mesh, and add your chosen
primitive. In this example, we\'ll be using a Cone.

! A basic cone in Edit
Mode{width="220"}

Do everything with the 3D cursor at the center.

-   Set your view to the X-Y Axis (Top View) by pressing **NUM7**, the 7
    on the keypad.
-   Press *\'Shift+A \>*Mesh*\>*Cone\'\'
-   A smaller number of vertices are needed, since this cone will become
    just the tip of the finished shape.
-   Reduce the number of vertices to 12.
-   Press **TAB** to enter Edit Mode, or choose Edit Mode from the
    bottom of the 3D viewport.
-   Switch views to the Z-X Axis by pressing **NUM1** (1 on the keypad).
    Your screen should now look something like the picture at left.
-   If your cone is selected (one or more vertices are yellow) press
    **AKEY** (Select/Deselect All) until they are deselected.
-   Select the point of your Cone with the **RMB** and drag it upwards
    with the blue arrow. You can hold down the **CONTROL** key if you
    want to constrain the scaling to set units. For this example, 5
    squares of height were added to the cone.

### Subdividing the Cone

!Extruded cone{width="100"}

-   Go to front view by pressing **NUM1**

The best way to do it is by selecting the side edges and subdivide them
by pressing **WKEY** then clicking on *Subdivide*, after that you can
select the number of cuts you want. You need at least \"5\" segments.
The more segments you have, the smoother your curved cone will be. be
sure you have \"Limit selection to visible off\" and to first deselect
all \"A key\" and you are in \"edge select\" mode

-   You can also do: still in Edit Mode, press the **NUM8** repeatedly
    to rotate your view to the underside of your cone. Select the center
    vertex of the circle, and hold down **CONTROL**, then press the
    **+KEY** on the keypad. This will select all of the adjacent
    vertices of the base. Then extrude using the **EKEY** Pull the new
    vertices away from the cone a distance at the Z-axis and click the
    **LMB** to set them in place. Press the **SKEY** and widen the new
    base of the cone a bit.

### Making a Curve

![](ConeCurve3.jpg){width="100"}

-   In Object Mode, Z-X orientation (**NUM1**\'), make sure you have
    nothing selected and press *\'Shift+A* \> *Curve* \> *Bezier Curve*
-   Rotate your curve 90° (holding down the **CONTROL** key to make it
    rotate in 5° intervals) Note- or just R-KEY and then type 90, so
    that it lines up with your cone. Move it off to one side so that its
    not hidden by your cone.
-   Go into \"wireframe\"
-   Grab the center vertex of each end and adjust its rotation
    (**RKEY**) until you have a nice shallow dome shape.
-   Scale the curve in size (**SKEY**) until it is larger than your
    cone.
-   The name is highlighted in the \"Outliner\" Window: \"BezierCurve\"

### Applying the Curve to the Mesh

!Modified cone{width="120"}

-   Select the cone in Object Mode. Choose in the \"Properties\" Header
    the \"modifiers\" tab and click \"Add Modifier\"
-   Click the *Add Modifier* button and choose *Curve* from the popup
    list.
-   Under Object tick the empty box, and select the name of the \"Bézier
    Curve\" (it will be \"BezierCurve\" without the quotations if you
    left it as the default.)
-   Notice the six buttons underneath, They are **X, Y, Z, -X, -Y, -Z**.
    They affect which plane the curve deforms. For this example, you\'ll
    need to select the **X** button.
-   Move your Cone so that it overlays the curve in the \'3D View\"
    windows, and notice how it follows the Bézier Curve.
-   You can modify the Bézier Curve as well as the cone repeatedly until
    you are happy with the design.
-   If you switch to Edit Mode, notice that the cone returns to its
    straight orientation.
-   To apply the deformation to the mesh permanently, in the Modifiers
    panel, click the *Apply* button next to your Curve modifier.
-   Move the curve up \'till the cone is around the curve

