How to create a very shallow rounded edges bowl shape in the side of a cylinder?

Question

I plan to do this multiple times for multiple points along the cylinder (like a spiral), so it would be good if the method is:

1. Easy and quick
2. Or: copy-able to other areas in the cylinder

I have a cylinder, and I want to insert a shape onto it, with a very very subtle inward push like so:

So if this is my cylinder, it would look like this from the side:

And most preferably it's also parametric so that I can later modify:

1. how deep the bowl is
2. the shape of the curve inwards
3. And have that affect all other bowls that are inside the cylinder.

I already tried doing this by loop cutting the cylinder so that I have a grid, then cutting a square, then making a circle extruding it, and shrink wrapping it to the cylinder, then joining it to the cylinder, then filling in faces for the empty parts, then subdividing (which introduces other problems as other parts of the cylinder I don't want subdivided a second time.)

Here are my awful and very work-intensive results (which I would not like to repeat):

Then subdividing which gets closer to the shape but introduces problems in other areas of the cylinder:

But even then, the circle is too deep and is not easily modifiable, nor copy-able, and as you can see has some awful looking holes that I just couldn't fix with adding faces.

Note: Beginner...may seem like I know something... I don't know anything! Please be detailed when responding

Answer 1

I would go about it something like this - it's not "parametric" per se, but it's rather easy to implement so it might be a happy trade-off. Since you only need a small influence to the "dent", I would recommend omitting the subtracting of faces and shrink-wrapping, and instead use Proportional Editing.

First step is to isolate the section of the cylinder where you want the "dent" to be:

Then add enough loop cuts so the individual "cells" are as close to square shape as possible (I take it you've already done this):

Pick a vertex in the center of your "grid" on one side (preferably one of the "cardinal" directions for ease of making the shape later). Turn on Proportional Editing (O), and select one of the edit options from the top - I recommend Inverse Square (I know "sphere" is selected in the photo - ignore it) however feel free to try different options and see what works best for your project.

Grab the vertex (G) and move it along whatever axis it's aligned to (so it can move towards the center of the cylinder). The size of the blue edit circle controls the size of the edit influence - you can adjust it by scrolling the Mouse Wheel. Move the vertex inwards:

Final shape looks like this (with subdivision surface and smooth shading):