There are some really nice video-tutorials out there in the internets that show who to animate a growing vine in blender - unfortunately all I found are for blender 2.48 and use keyboard shortcuts that aren't working in blender 2.5/2.6 anymore.
so I tried to recreate them for the current blender-version. Here is a short video to show what the final animation looks like.
To make a vine in blender 3 curves are needed. The first one defines the curve the vine will grow along, the second one defines the shape of the cross-section, and the third one defines the thickness of the vine.
So first define a bezier-curve by pressing Shift-A and selecting curve and bezier
define the curve your vine should grow along by switching to edit mode and etxtruding the last vertex some times (press tab to go to edit mode and e to extrude)
then add a bezier-circle and scale it down a bit
now select the first beziercurve by clicking it with the right mousebutton and select the object data-section on blender-menue on the right side
down in the geometry section click on the bevel object and select the bezier-circle
This should make the vine look like a tube curling along your path.
Now add a second bezier curve, select it with the right mousebutton and switch to edit mode
select all vertices by pressing A and scale them to 0 along the y axis by pressing S Y and 0
then extrude the left vertex 2 blenderunits along the y-axis by pressing E Y 2 and enter
select the vertex on the top and the vertex at the corner and scale them to zero along the x-axis by pressing S X 0
your curve should look like this
This curve will be used to define the width of the vine. So press tab again and select your first bezier-curve
go to the geometry section again and add the new bezier-curve as a taper object to the first one
if you select the second bezier curve now and move around the corner-vertex you can watch the vine grow and shrink along the first curve. Which is exactly what we want to animate, but we cant keyframe a single vertex.
The trick that most video-tutorials use is adding an empty-object as a hook to the vertex. so if the empty gets animated the vertex we hooked will move along.
To add a new hook select the second bezier-curve and go to edit mode. Select the corner-vertex and press space
then enter hook and select hook to new Object
This adds an empty-object to your scene that is hooked to the corner vertex. if you select the empty object in object-mode and translate it along the x-axis (press G X and move the mouse) your vine should grow and shrink.
The movements of this empty object can be animated using key-frames so move your empty all to the left and add a keyframe by pressing I and select Location
now advance some frames in the timeline at the bottom then move the empty along the x-axis by pressing G X and moving it to the right
then add another keyframe by pressing I and selecting location again.
when you click the play button at the bottom your vine should get animated and grow along the path
I'm sure this isn't the only way to achive the desired effect but it's the easierst I can think of at the moment
you can download my blend-file here
hope this helps a bit, and happy vine growing :-)
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