How to project a Helix in a curved cylinder


Now I understand what you meant by 'curved cylinder'. I didn't pick up on that. Here's a brief, simplified demonstration:

  1. Step 1:

    Once you've established the form of the bottle, the first step is to create a helix concentric to the bottle.

  2. Step 2:

    You will use this helix as the path of a spiral 'swept surface' feature.

  3. Step 3:

    Then you create a 3d sketch and select the bottle surface and the spiral surface and use the 'intersection curve' tool to create the helical path that follows the bottle curvature.

  4. Step 4:

    Finally, use this 3d sketch as the path in the 'swept cut' feature that forms your helical grip.

  5. Step 5:

    I've attached the model used in this tutorial in case it can be of help. I'm sure your bottle and grip will be much more beautiful than mine, this was just a quick demonstration of the features you'll need.