hi,
If you take a look at
http://wiki.blender.org/index.php/Manual/PartII/Curves
you will find following description:
For adjusting proper size of Bevel effect for individual curve’s segment use Set Radius option accessable through W-4. Default value is 1.0.
Caution: no Bevel Effect if bevel Radius parameter set to 0.0.
How does this feature work ? I can’t make it working at all.
Thanks,
ygs
For that example, a simpler way would be to use Alt + S instead.
It should work out of the box in your Curve (using a BevelObject as Bevel).
ygs,
It does work.
Create a curve.
Then create a CurveCircle.
Scale the circle down a bit.
Then select the curve and assign the CurveCircle as the Bevel Object.
Then got into edit mode of the curve and select a single vertex.
Press W-4 and set the radius to something small like 0.01.
TAB out of edit mode and you will have a curve with a customised TAPER.
I think it is probably easier to simply use another curve for tapering the orignal curve rather than editing every single vertex. But the control is there if you want to do it that way.
yes, it works for me.Thank you, guys.
Earlier I used TAPER object to adjust bevel size, it’s more powerfull feature than this one.
It would be much valuable if TAPER object and this SET RADIUS option
could be stuck to needed axis OR just to current VIEW.
Also it would be super, if modeller could use several bevel curves at once
Some days ago I tried to express the idea here
http://blenderartists.org/forum/showthread.php?t=139790
Does anybody know how to contact with the developer of these
BEVEL/TAPER features ?
hi ygs,
Since you know now how it works, then maybe you have an idea how explain it better on this wiki page? I am not native in english, so any help appreciated. 
hi migius,
I’m not an English speaking man too. I’m from Ukraine. 
I can try to describe this feature and post here a little bit later, if you like.
Anyway we will need someone to edit grammar and stylisticts 
ygs
I see no advantage to using this method. It is easier to use a taper curve.