My first printing attempt was with a suction cup hook.
It looks good, but after printing it, I realized its hole was too big for my suction cups.
So I decided to edit the model to fix that.
At first, I tried editing the model directly, but I just messed up with the mesh.
shrinking the model
I can simply resize the model until the size of the hole is ok. I don’t want the model to become too weak, so I will only resize along the plan orthogonal to the hole axis.
Let’s take the measurements first.
The inner diameter is about 4 mm and the outer diameter about 7mm. Lets use as target 5mm and 10mm.
Darn! The cup is not aligned on the axes!
So let’s try to approximately rotate it so that we will be able to scale along only 2 dimensions.
After playing a bit with the cursor and rotation, grabbing, I eventually get something that I consider good enough.
I have something that is approximately 5.5mm by 7.5mm.
cura already has a feature to print the part with the selected surface on the table, so I don’t need to revert my previous rotation.
The end result is not as nice as I expected, but eventually, I could set it up and the result appears to be good enough.
After some time though, the hook breaks. It looks like shrinking it made it too weak.
trying taking advantage of boolean operators
It can try recreating the part with the hole by simply making a rectangle minus two cylinders.
I can then union this part with the original mesh.
Since I making the hole from scratch, I need a few more measurements.
It seems like I only need to have a hole of around 5mm for the small circle and around 10 mm for the outer circle. It should have a depth of between 1mm and 2mm.
Something like that should do the trick.
I also applied the remesh operator to avoid future issues with a mesh inside another mesh and non manifold stuff.
The result is not aesthetically perfect, but the suction cup fits well enough.
After some time, the hooks that supported big towels broke. Also, sometimes, the hook gets out of the suction cup.
So I guess this is a good time for another attempt.
making the hole event longer
To make it stronger, I simply need to make the supporting part bigger. And increasing the hole length should help the suction cup stick with it. Finally, I reduced the depth of this part to leave room for the suction cup and attach it without warping it.
I eventually got to this model.
Again, this is not very beautiful, but it is a part that is hidden, so who cares? At least I don’t.
For the record, it been a few months since I printed the hooks, and not only no hook broke so far. Also, I believe that making more room for the suction cup lead led to making it stick better on the wall. So far, almost 6 month later, the suction cup has not fallen yet.