<p>I'm pretty new to 3D printing but I was fairly sure I could get this to print nicely without supports and I did it! First here are some things I tried:</p>
<ol>
<li>I tried the manual supports suggested by fred_dot_u, unfortunately, it does not really work in this case. It seems like the bridge needs a reasonable width of support at each end to adhere to.</li>
</ol>
<p><a href="https://i.sstatic.net/Uam0x.jpg" rel="nofollow noreferrer" title="Photo of a 3D printed model with the supports failing"><img src="https://i.sstatic.net/Uam0x.jpg" alt="Photo of a 3D printed model with the supports failing" title="Photo of a 3D printed model with the supports failing" /></a></p>
<ol start="2">
<li>I redesigned my model to not have 90° overhangs. Fortunately, in my case I can actually get away with 45° slops and also a 67° slope like this (this is upside down compared to the images in the question).</li>
</ol>
<p><a href="https://i.sstatic.net/3oKl7.png" rel="nofollow noreferrer" title="A sketch showing the model redesigned with 45-degree angles to minimize support usage"><img src="https://i.sstatic.net/3oKl7.png" alt="A sketch showing the model redesigned with 45-degree angles to minimize support usage" title="A sketch showing the model redesigned with 45-degree angles to minimize support usage" /></a></p>
<p>Unfortunately, this did not print at all well with the default Cura settings. It still insists on doing the &quot;wall&quot; rings first and those have no support.</p>
<p><a href="https://i.sstatic.net/n5YEu.jpg" rel="nofollow noreferrer" title="Photo of the printed model with a slightly better surface but missing printed elements"><img src="https://i.sstatic.net/n5YEu.jpg" alt="Photo of the printed model with a slightly better surface but missing printed elements" title="Photo of the printed model with a slightly better surface but missing printed elements" /></a></p>
<p>(The black dots are from wet and dry paper.)</p>
<ol start="3">
<li>I managed to get it to print in the right order - spiraling inwards - by slicing with PrusaSlicer and just setting the wall width really high, like 5. It worked a bit better, but still 67° overhang was too much for my printer, and also I don't really want walls that thick.</li>
</ol>
<p><a href="https://i.sstatic.net/d0rjy.png" rel="nofollow noreferrer" title="Screenshot of PrusaSlicer's model preview showing the start of the layer"><img src="https://i.sstatic.net/d0rjy.png" alt="Screenshot of PrusaSlicer's model preview showing the start of the layer" title="Screenshot of PrusaSlicer's model preview showing the start of the layer" /></a></p>
<p><a href="https://i.sstatic.net/abFB4.png" rel="nofollow noreferrer" title="Screenshot of PrusaSlicer's model preview showing the end of the layer"><img src="https://i.sstatic.net/abFB4.png" alt="Screenshot of PrusaSlicer's model preview showing the end of the layer" title="Screenshot of PrusaSlicer's model preview showing the end of the layer" /></a></p>
<p><a href="https://i.sstatic.net/t0ZkU.png" rel="nofollow noreferrer" title="Photo of the model with better surfaces but still failing"><img src="https://i.sstatic.net/t0ZkU.png" alt="Photo of the model with better surfaces but still failing" title="Photo of the model with better surfaces but still failing" /></a></p>
<ol start="4">
<li>Finally I realised what I should do. Bridging seems to work well over long distances, as long as both ends are well supported. So all I need to do is manually add some &quot;bridge supports&quot; and convince Cura to print them as actual bridges. Here's my CAD (I've resorted to just a test piece rather than my actual model now):</li>
</ol>
<p><a href="https://i.sstatic.net/3UYWi.png" rel="nofollow noreferrer" title="Screenshot of a new design in CAD design with manually added bridge supports"><img src="https://i.sstatic.net/3UYWi.png" alt="Screenshot of a new design in CAD design with manually added bridge supports" title="Screenshot of a new design in CAD design with manually added bridge supports" /></a></p>
<p>Essentially I added a 0.2 mm layer extrusion down everywhere except a square in the middle, and then a further 0.2 mm extrusion down in these purple areas:</p>
<p><a href="https://i.sstatic.net/cDz70.png" rel="nofollow noreferrer" title="Screenshot of the new design with bridge supports"><img src="https://i.sstatic.net/cDz70.png" alt="Screenshot of the new design with bridge supports" title="Screenshot of the new design with bridge supports" /></a></p>
<p>Then when you slice in Cura set <strong>Top/Bottom Line Directions</strong> to <strong>[0, 90]</strong> (or perhaps you could just rotate the square by 45°), and it will slice it like this:</p>
<p><a href="https://i.sstatic.net/eVgbU.jpg" rel="nofollow noreferrer" title="Screenshot of Cura's preview of the model's first layer"><img src="https://i.sstatic.net/eVgbU.jpg" alt="Screenshot of Cura's preview of the model's first layer" title="Screenshot of Cura's preview of the model's first layer" /></a></p>
<p><a href="https://i.sstatic.net/fxX0g.jpg" rel="nofollow noreferrer" title="Screenshot of Cura's preview of the model's second layer"><img src="https://i.sstatic.net/fxX0g.jpg" alt="Screenshot of Cura's preview of the model's second layer" title="Screenshot of Cura's preview of the model's second layer" /></a></p>
<p>And it prints perfectly!</p>
<p><a href="https://i.sstatic.net/LlDto.jpg" rel="nofollow noreferrer" title="Photo of the printed model properly printed and no failures"><img src="https://i.sstatic.net/LlDto.jpg" alt="Photo of the printed model properly printed and no failures" title="Photo of the printed model properly printed and no failures" /></a></p>
<p>Ok, in the end, I think I might not do that because I realised I can redesign it to use 45° slopes and a big closed hole at the top... but I'm glad I proved that you <em>can</em> do 90° overhangs with holes in them without supports.</p>

CC BY-SA 4.0
2023-01-17T13:02:46.100Z
By changing the design yes, but that was not in the original question (it was asking about spiralizing contours, this is possible, see https://www.youtube.com/watch?v=c9b7Ey4LyCs, albeit with experimental slicers). You could have made it even more easy by covering the holes completely with a 0.2 or 0.4 mm layer, that is pretty common, you later remove the fine surface to recover the hole.
0scar
CC BY-SA 4.0
2023-01-17T15:52:07.353Z
The design is *barely* changed - only by 2 extra partial layers. And yeah I am aware of the various attempts to spiralize contours (fullcontrol.xyz and arc overhangs) but neither of those fit the bill here. `fullcontrol.xyz` looks entirely hand-coded and arc overhangs isn't supported by Cura or PrusaSlicer. As far as I know neither of them have a handy scripting layer so I would have to modify the engine which is a bit too much work.
Timmmm
CC BY-SA 4.0
2023-01-17T16:41:49.310Z
Good to see that you explored various things and reported them in an answer, you can accept the answer after 48 hours. The technique you used in the final part of the answer is a well known solution to do this, kudos you engineered this yourself!
0scar
CC BY-SA 4.0
2023-01-30T22:55:33.233Z
Now I see what you did. You removed "overhangs" from your model, now you only have "bridges". Nice job. There are many ways to remove overhangs, this is one of them. Printing with supports isn't a big deal really with the right settings. And there's always 3D printers with dual extruders where you can use water soluble supports. If you make lots of technical parts you might wanna look into them. Makes life a lot easier.
AzulShiva
CC BY-SA 4.0
2023-01-17T10:07:08.880Z
2023-01-17T13:49:32.047Z
2023-01-17T13:49:32.047Z
Timmmm
<p>Angus of Maker's Muse has a <a href="https://www.youtube.com/watch?v=RPijCjz9G1w" rel="nofollow noreferrer">video</a> which may be of value. He suggests to create additional components to the model that become supports. I've used this method with great results. The specific model I created contained counterbores that could not be inverted and would have required supports and also would have become a mess to remove.</p>
<p><a href="https://i.sstatic.net/nrKN6.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/nrKN6.png" alt="cylindrical support" /></a></p>
<p>The black lines represent a pair of cylinders of nearly matching diameters. The larger cylinder should be the same diameter and the second cut plus one or two nozzle widths, to allow overlap. This creates a bridging circumstance of relatively small dimensions.</p>
<p>This support cylinder could be hollow, but the slicer will have to bridge the top of it in order to create the center cylinder support. One could create a solid cylinder with a cone removed, allowing the print to build a non-supported taper to the top, but it would be easier to create a pair of nested cylinders, both of which could be hollow.</p>
<p>As before, the center cylinder should be the same diameter as the top most cut, plus the nozzle width times to create the bridging feature.</p>
<p><a href="https://i.sstatic.net/dEK9h.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/dEK9h.png" alt="two nested cylinders" /></a></p>

CC BY-SA 4.0
2023-01-16T12:53:23.373Z
For info: the extra component that will work as supports can be added directly in the slicer, no need to change the model. And of course printing on the flat side is also an option.
FarO
CC BY-SA 4.0
2023-01-16T13:17:04.137Z
I tried this and it *kind of* worked. See [this photo](https://github.com/Ultimaker/Cura/issues/14296#issuecomment-1383179874). Unfortunately bridging to 1-extrusion-thick wall does not really work. However it has given me another idea that I will try...
Timmmm
CC BY-SA 4.0
2023-01-14T12:07:56.747Z
2023-01-14T12:07:56.747Z
fred_dot_u
<p>Here are your settings. The ones with the arrows are especially important. Just copy everything I've underlined with red and everything will work fine ;-)</p>
<p><a href="https://i.sstatic.net/wbH8t.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wbH8t.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2023-01-30T22:43:53.033Z
I appreciate the help but I don't think it really answers the question - I was trying to print *without* supports. Also if you check my answer you can see that I came up with a much better method that does allow printing without supports (with very minor model changes).
Timmmm
CC BY-SA 4.0
2023-01-30T22:46:59.700Z
@Timmmm Yes I'm aware of that. I answered this after I read your comment: "However I actually did try with supports and it still gave bad results. The issue is it prints the inner circle floating in space (there are supports underneath but 0.4mm away so it doesn't really help. Then all of the bridges to the inner circle do not stick to it."
AzulShiva
CC BY-SA 4.0
2023-01-30T22:47:34.413Z
I simply gave you an answer how to use supports properly, since your settings are wrong. A model like that should really be printed with supports.
AzulShiva
CC BY-SA 4.0
2023-01-31T08:22:58.367Z
Yeah I think the default Cura settings have a 2 layer gap which is just way too much. But in any case it shouldn't be printed with supports because you can get better results without supports.
Timmmm
CC BY-SA 4.0
2023-01-31T13:37:55.257Z
@Timmmm Better results without supports? I don't think so.
AzulShiva
CC BY-SA 4.0
2023-01-31T15:11:56.863Z
Well I do and I've actually printed it so...
Timmmm
CC BY-SA 4.0
2023-01-30T22:05:21.363Z
2023-01-30T22:05:21.363Z
AzulShiva
<p>I am trying to print an object with this cross section (the full object is just this mirrored):</p>
<p><a href="https://i.sstatic.net/r1cDx.png" rel="nofollow noreferrer" title="Object"><img src="https://i.sstatic.net/r1cDx.png" alt="Object" title="Object" /></a></p>
<p>The problem is that big overhang layer. Cura slices it like this:</p>
<p><a href="https://i.sstatic.net/52SrT.jpg" rel="nofollow noreferrer" title="Bad slice"><img src="https://i.sstatic.net/52SrT.jpg" alt="Bad slice" title="Bad slice" /></a></p>
<p>This is obviously going to fail. Is there any way to make Cura slice it in a spiral inwards from the outside, something like this (excuse the terrible diagram):</p>
<p><a href="https://i.sstatic.net/gLUbJ.png" rel="nofollow noreferrer" title="Good slice"><img src="https://i.sstatic.net/gLUbJ.png" alt="Good slice" title="Good slice" /></a></p>

CC BY-SA 4.0
2023-01-15T13:41:01.750Z
Is there a reason for not using supports?
0scar
CC BY-SA 4.0
2023-01-16T13:15:20.877Z
Yeah in theory I think it could print without them, and they take time to print. However I actually did try with supports and it still gave bad results. The issue is it prints the inner circle floating in space (there are supports underneath but 0.4mm away so it doesn't really help. Then all of the bridges to the inner circle do not stick to it.
Timmmm
CC BY-SA 4.0
2023-01-16T14:05:05.840Z
In theory you cannot print large overhangs (unless you print slow and cool properly) and certainly not when there is a wall (hole) to be printed in the middle without changing your design. There are mods to spiralize such area's, but that is very experimental. You don't need a distance of 0.4 mm, 0.2 mm works fine (you can use an interface layer) but be sure to cool that layer more than normal. If properly sliced and printer properly setup, this prints fine with support.
0scar
CC BY-SA 4.0
2023-01-30T22:11:18.700Z
For printing large BRIDGES without supports you'll want to cool MUCH and print FAST. LARGE nozzle diameter and HIGH layer height. Overhangs are a different story...
AzulShiva
<ultimaker-cura><slicing>
Print overhangs from the edges in
Timmmm
# Print overhangs from the edges in

(Asked by: username_0 on 2023-01-14)

I am trying to print an object with this cross section (the full object is just this mirrored):

[![Object](https://i.sstatic.net/r1cDx.png "Object")](https://i.sstatic.net/r1cDx.png "Object")

The problem is that big overhang layer. Cura slices it like this:

[![Bad slice](https://i.sstatic.net/52SrT.jpg "Bad slice")](https://i.sstatic.net/52SrT.jpg "Bad slice")

This is obviously going to fail. Is there any way to make Cura slice it in a spiral inwards from the outside, something like this (excuse the terrible diagram):

[![Good slice](https://i.sstatic.net/gLUbJ.png "Good slice")](https://i.sstatic.net/gLUbJ.png "Good slice")

**Tags:** ultimaker-cura, slicing
> **Comments:**
> **username_1**: Is there a reason for not using supports?  
> **username_0**: Yeah in theory I think it could print without them, and they take time to print. However I actually did try with supports and it still gave bad results. The issue is it prints the inner circle floating in space (there are supports underneath but 0.4mm away so it doesn't really help. Then all of the bridges to the inner circle do not stick to it.  
> **username_1**: In theory you cannot print large overhangs (unless you print slow and cool properly) and certainly not when there is a wall (hole) to be printed in the middle without changing your design. There are mods to spiralize such area's, but that is very experimental. You don't need a distance of 0.4 mm, 0.2 mm works fine (you can use an interface layer) but be sure to cool that layer more than normal. If properly sliced and printer properly setup, this prints fine with support.  
> **username_2**: For printing large BRIDGES without supports you'll want to cool MUCH and print FAST. LARGE nozzle diameter and HIGH layer height. Overhangs are a different story...  

---

## 3 answers

### Answer by username_0 on 2023-01-17. Score: 3 | Accepted answer

I'm pretty new to 3D printing but I was fairly sure I could get this to print nicely without supports and I did it! First here are some things I tried:

1. I tried the manual supports suggested by fred\_dot\_u, unfortunately, it does not really work in this case. It seems like the bridge needs a reasonable width of support at each end to adhere to.

[![Photo of a 3D printed model with the supports failing](https://i.sstatic.net/Uam0x.jpg "Photo of a 3D printed model with the supports failing")](https://i.sstatic.net/Uam0x.jpg "Photo of a 3D printed model with the supports failing")

2. I redesigned my model to not have 90° overhangs. Fortunately, in my case I can actually get away with 45° slops and also a 67° slope like this (this is upside down compared to the images in the question).

[![A sketch showing the model redesigned with 45-degree angles to minimize support usage](https://i.sstatic.net/3oKl7.png "A sketch showing the model redesigned with 45-degree angles to minimize support usage")](https://i.sstatic.net/3oKl7.png "A sketch showing the model redesigned with 45-degree angles to minimize support usage")

Unfortunately, this did not print at all well with the default Cura settings. It still insists on doing the "wall" rings first and those have no support.

[![Photo of the printed model with a slightly better surface but missing printed elements](https://i.sstatic.net/n5YEu.jpg "Photo of the printed model with a slightly better surface but missing printed elements")](https://i.sstatic.net/n5YEu.jpg "Photo of the printed model with a slightly better surface but missing printed elements")

(The black dots are from wet and dry paper.)

3. I managed to get it to print in the right order - spiraling inwards - by slicing with PrusaSlicer and just setting the wall width really high, like 5. It worked a bit better, but still 67° overhang was too much for my printer, and also I don't really want walls that thick.

[![Screenshot of PrusaSlicer's model preview showing the start of the layer](https://i.sstatic.net/d0rjy.png "Screenshot of PrusaSlicer's model preview showing the start of the layer")](https://i.sstatic.net/d0rjy.png "Screenshot of PrusaSlicer's model preview showing the start of the layer")

[![Screenshot of PrusaSlicer's model preview showing the end of the layer](https://i.sstatic.net/abFB4.png "Screenshot of PrusaSlicer's model preview showing the end of the layer")](https://i.sstatic.net/abFB4.png "Screenshot of PrusaSlicer's model preview showing the end of the layer")

[![Photo of the model with better surfaces but still failing](https://i.sstatic.net/t0ZkU.png "Photo of the model with better surfaces but still failing")](https://i.sstatic.net/t0ZkU.png "Photo of the model with better surfaces but still failing")

4. Finally I realised what I should do. Bridging seems to work well over long distances, as long as both ends are well supported. So all I need to do is manually add some "bridge supports" and convince Cura to print them as actual bridges. Here's my CAD (I've resorted to just a test piece rather than my actual model now):

[![Screenshot of a new design in CAD design with manually added bridge supports](https://i.sstatic.net/3UYWi.png "Screenshot of a new design in CAD design with manually added bridge supports")](https://i.sstatic.net/3UYWi.png "Screenshot of a new design in CAD design with manually added bridge supports")

Essentially I added a 0.2 mm layer extrusion down everywhere except a square in the middle, and then a further 0.2 mm extrusion down in these purple areas:

[![Screenshot of the new design with bridge supports](https://i.sstatic.net/cDz70.png "Screenshot of the new design with bridge supports")](https://i.sstatic.net/cDz70.png "Screenshot of the new design with bridge supports")

Then when you slice in Cura set **Top/Bottom Line Directions** to **[0, 90]** (or perhaps you could just rotate the square by 45°), and it will slice it like this:

[![Screenshot of Cura's preview of the model's first layer](https://i.sstatic.net/eVgbU.jpg "Screenshot of Cura's preview of the model's first layer")](https://i.sstatic.net/eVgbU.jpg "Screenshot of Cura's preview of the model's first layer")

[![Screenshot of Cura's preview of the model's second layer](https://i.sstatic.net/fxX0g.jpg "Screenshot of Cura's preview of the model's second layer")](https://i.sstatic.net/fxX0g.jpg "Screenshot of Cura's preview of the model's second layer")

And it prints perfectly!

[![Photo of the printed model properly printed and no failures](https://i.sstatic.net/LlDto.jpg "Photo of the printed model properly printed and no failures")](https://i.sstatic.net/LlDto.jpg "Photo of the printed model properly printed and no failures")

Ok, in the end, I think I might not do that because I realised I can redesign it to use 45° slopes and a big closed hole at the top... but I'm glad I proved that you *can* do 90° overhangs with holes in them without supports.

> **Comments:**
> **username_1**: By changing the design yes, but that was not in the original question (it was asking about spiralizing contours, this is possible, see https://www.youtube.com/watch?v=c9b7Ey4LyCs, albeit with experimental slicers). You could have made it even more easy by covering the holes completely with a 0.2 or 0.4 mm layer, that is pretty common, you later remove the fine surface to recover the hole.  
> **username_0**: The design is *barely* changed - only by 2 extra partial layers. And yeah I am aware of the various attempts to spiralize contours (fullcontrol.xyz and arc overhangs) but neither of those fit the bill here. `fullcontrol.xyz` looks entirely hand-coded and arc overhangs isn't supported by Cura or PrusaSlicer. As far as I know neither of them have a handy scripting layer so I would have to modify the engine which is a bit too much work.  
> **username_1**: Good to see that you explored various things and reported them in an answer, you can accept the answer after 48 hours. The technique you used in the final part of the answer is a well known solution to do this, kudos you engineered this yourself!  
> **username_2**: Now I see what you did. You removed "overhangs" from your model, now you only have "bridges". Nice job. There are many ways to remove overhangs, this is one of them. Printing with supports isn't a big deal really with the right settings. And there's always 3D printers with dual extruders where you can use water soluble supports. If you make lots of technical parts you might wanna look into them. Makes life a lot easier.  

---

### Answer by username_3 on 2023-01-14. Score: 2

Angus of Maker's Muse has a [video](https://www.youtube.com/watch?v=RPijCjz9G1w) which may be of value. He suggests to create additional components to the model that become supports. I've used this method with great results. The specific model I created contained counterbores that could not be inverted and would have required supports and also would have become a mess to remove.

[![cylindrical support](https://i.sstatic.net/nrKN6.png)](https://i.sstatic.net/nrKN6.png)

The black lines represent a pair of cylinders of nearly matching diameters. The larger cylinder should be the same diameter and the second cut plus one or two nozzle widths, to allow overlap. This creates a bridging circumstance of relatively small dimensions.

This support cylinder could be hollow, but the slicer will have to bridge the top of it in order to create the center cylinder support. One could create a solid cylinder with a cone removed, allowing the print to build a non-supported taper to the top, but it would be easier to create a pair of nested cylinders, both of which could be hollow.

As before, the center cylinder should be the same diameter as the top most cut, plus the nozzle width times to create the bridging feature.

[![two nested cylinders](https://i.sstatic.net/dEK9h.png)](https://i.sstatic.net/dEK9h.png)

> **Comments:**
> **username_4**: For info: the extra component that will work as supports can be added directly in the slicer, no need to change the model. And of course printing on the flat side is also an option.  
> **username_0**: I tried this and it *kind of* worked. See [this photo](https://github.com/Ultimaker/Cura/issues/14296#issuecomment-1383179874). Unfortunately bridging to 1-extrusion-thick wall does not really work. However it has given me another idea that I will try...  

---

### Answer by username_2 on 2023-01-30. Score: 0

Here are your settings. The ones with the arrows are especially important. Just copy everything I've underlined with red and everything will work fine ;-)

[![enter image description here](https://i.sstatic.net/wbH8t.jpg)](https://i.sstatic.net/wbH8t.jpg)

> **Comments:**
> **username_0**: I appreciate the help but I don't think it really answers the question - I was trying to print *without* supports. Also if you check my answer you can see that I came up with a much better method that does allow printing without supports (with very minor model changes).  
> **username_2**: @Timmmm Yes I'm aware of that. I answered this after I read your comment: "However I actually did try with supports and it still gave bad results. The issue is it prints the inner circle floating in space (there are supports underneath but 0.4mm away so it doesn't really help. Then all of the bridges to the inner circle do not stick to it."  
> **username_2**: I simply gave you an answer how to use supports properly, since your settings are wrong. A model like that should really be printed with supports.  
> **username_0**: Yeah I think the default Cura settings have a 2 layer gap which is just way too much. But in any case it shouldn't be printed with supports because you can get better results without supports.  
> **username_2**: @Timmmm Better results without supports? I don't think so.  
> **username_0**: Well I do and I've actually printed it so...  

---

