Unwanted and inconsistent support structure

[H4NNE5 0]

Hi, 
In my design I have a horizontal hole inside my print and Cura wants to generate these structures. I tried normal and tree support and fiddled with the settings but it won't disappear.
And on top, the support is OUTSIDE of the print and not supporting the print at all.
Also in normal mode, it generates a layer around the model at the bottom which is also located outside of the model's ground face.


Any ideas how that is possible?

Thanks for the attention.
Hannes

Edited May 19, 2024 by H4NNE5

[Slashee_the_Cow 619]

If the bottom edge of the model is slightly curved (hard to tell from the screenshots but it sorta looks like it), the support would most likely want to support that.

 

Staying outside the model is likely because of the Support > Support X/Y Distance setting. By default it's 0.8mm, meaning support will always stay at least 0.8mm away from a wall. In your case it looks like that might be set pretty high.

 

If you could post your Cura project file (.3mf, get it set up, then go to File > Save Project) we can have a look at the model and your settings and be able to figure out what's to blame.

 

Meanwhile, let me introduce you to a new friend: the support blocker. With your model selected, it's this button on the toolbar on the left:

Now let me introduce you to one of my friends:

He doesn't say much. He's really only useful for testing things. But you see the bit on the left where it goes over itself and produces support that sits on top of the lower part of the model? That support is really annoying to try and get rid of. And I have faith that my printer can bridge that gap without it. So:

1. Select your model by clicking on it
2. Click the support blocker button in the toolbar 
3. Click on your model (not on the support) in roughly the area you want it to be (you'll have to move and resize it anyway). I'm going back to "prepare" mode for this because it's much easier to see the blockers:
   
4. It's not in quite the right place and it's too big. It always just generates a 10x10x10mm cube. So click on the move tool  on the left toolbar then click on your support blocker and move it into roughly the right place:
   
5. Still not the right size. Click on the scale tool  turn on Snap Scaling and turn off Uniform Scaling  and then drag the handles until it's the right size. It usually doesn't matter if it overlaps the model a bit. You can turn off snap scaling to fine tune it if you want, but personally I just change the numbers if I have to. Anyway, let's scale it:
   
6. Now it's not in the right place. Repeat steps 4-5 until it's the right size in the right spot:
   
   Much better.
7. Switch back to Preview mode and admire your lack of supports:
   
8. Hang on, there's a naughty bit snuck in there. In my case that's because Support > Support Horizontal Expansion is set to 0.8mm (and I have no idea why because I usually have it set to 0 in my profile). So I'll just set that to 0mm:
   
   Much better.

You can bridge that gap, little... thing! I have faith in you.

(Yes it can bridge that gap, but only when using PLA, not PETG or TPU - they're too soft and stringy and fall down the gap.)

[H4NNE5 0]

Ok thank you very much for the hint with the support blocker. In my understanding it was, that it blocks supports for the whole model 😅

The changing of the X/Y setting was also making the understanding better.

Also I had the wrong definition of the overhang angle in my mind and set it to very low values. I thought it was measured from the base (horizontally), so low values would mean bigger overhangs.