How To Cut A Sine Shape On A Cylinder

Question

Trying drawing a sinelike shape on a cylinder

I am trying to draw the picture below. I tried using boolean modifier on the cylinder but, I couldn't create an object that would like on the picture below.

Any tips on how I can remove a shape from my cylinder that looks like on the picture below?

Answer 1

I assume you are having trouble with that curve. One way to create it would be to use edge loops and proportional editing. You want to make sure your cylinder has a slightly higher resolution, so the curve will be relatively smooth.

1. Go into edit mode and add an edge loop in the middle of your cylinder.
2. Select it with alt + your selection mouse button and search for checker deselect (my search button is F3). A new tab will appear, which lets you specify the offset etc. You want to only select the tips of your future curve.
3. Now, enable proportional editing by pressing O and hit G to move the vertices. You can adjust the editing radius with your mouse wheel and move the vertices forward until you have something that looks like half of a sinus curve.
4. Repeat these steps with the other half.
5. Now, create another edge loop underneath that looks the same by pressing ctrl + R and then E. Go into face select mode and select the curve with alt + selection button.
6. Extrude it and scale it inwards while locking the x-axis by pressing shift + X while scaling.

Answer 2

One way to do it is with curves converted to mesh, and then Boolean.

1. Go to Preferences > Add-on. Search for "extra" and check the box next to Add Curve: Extra Objects to activate this add-on. Also search for "loop" and check the box next to Mesh: LoopTools to activate this add-on.

2. Go to the 3D Viewport and press Shift + a and choose Circle (not the one under Bezier, but the one under Arc)

3. Open the menu at the bottom left corner (or press F6) and set the value of Sides to 12, and the value of Radius to 1.2 m. Have the buttons underneath set to: 3D, Bezier, Vector. And have the boxes next to "Cyclic" and "Show in edit mode" checked.

4. Select every other vertex (or control point) and move them 0.4 m in a direction perpendicular to the circle (z-axis).

5. Press Ctrl + I to select the other vertices. Press V to Set Handle Type and choose Vector.

6. Press Ctrl + I again to select the first set of vertices, and move them another 0.4 m in a direction perpendicular to the circle (z-axis). A total of 0.8 m.

7. Then copy and flip the curve. Press A and then Shift + D, and then Esc. Then press S, Z, -, 1, Enter.

8. Move the the duplicated curve 0.2 (or maybe 0.3 m) in a direction perpendicular to the circle (z-axis). And rotate it 30 degrees around the axis perpendicular to the circle (z-axis).

Then you should have something that looks like this.

9. Next go to object mode and press Alt + C and choose Mesh from Curve/Meta/Surf/Text. And go back to Edit Mode and press A to select all.

10. Press N for the N-panel to show if it doesn't already. Click the Edit tab. Extend the LoopTools menu, and extent the Circle menu. Lock the Z-axis by clicking the lock+Z icon and press Circle.

11. Then press Ctrl + E and choose Bridge Edge Loops. Press Alt + E and choose Extrude Faces Along Normals. Press for instance -.3Enter.

12. Add a Mesh > Cylinder, change the vertices value to 128, put a Boolean modifier on it and choose the Object named Circle as a target for the modifier.

Hide the Circle object and you're left with something like this.

(Image disclaimer: Boolen modifier applied, Smooth shaded, and Edge split modifier added)

You probably wont do exactly this but there probably is something in this method you can use : )