How to Bend Curve shape ideally on cylinder surface?

How to Bend Curve shape ideally on cylinder surface?

It all depends on what you want to bend and how you want it bent. Your question is too broad to give a specific answer. Try with a proper question with more detail, ideally with a clear illustration and blend showing what you exactly want.

I need to cut hole inside pipe wall. But the complex hole shape may not go outside or inside pipe surface (pipe viewed from top view as circle) but my hole edges are outside of circle. Also my pipe hole edges surrounding verteks data made few sectors of sircle not round but flat. I needed also there smooth edges not sharp.

There is an addon that makes various pipe joints for you, it may already be in 2.5, just goto your user preferences and turn it on.

also look at this tut —> http://www.blendercookie.com/2009/09/09/tip-cutting-a-hole-in-a-curved-surface/

Yes – that tut on retopo should help. In 2.5 to do retopo you enable snap to surfaces, then do retopo as usual.

Thank you, i try it out

Hi

It worked out perfectly, my model looks perfect now.
Thank u again.

Snap tool had to be activated in Blender 2.49.2, i snapped to median and some minimal manual editing.
Wireframe mode has to be off.