<p>The model has surfaces that are inverted. This is most notable with how the hole in the grip is turned into a cylinder, or the cutout in the blade being turned into a block.</p>
<p>To fix this, you need to fix the model.</p>

CC BY-SA 4.0
2023-08-23T22:53:43.840Z
I downloaded it from Cults3D and I have no idea how, I will try to find another model.
twitchsmh
CC BY-SA 4.0
2023-08-23T10:06:20.733Z
2023-08-23T10:06:20.733Z
Trish
<p>Bad model, as Trish says. Now onto how to fix it.</p>
<p>Install <a href="https://www.blender.org/" rel="nofollow noreferrer">Blender</a> and open it.</p>
<p><a href="https://i.sstatic.net/XZyib.png" rel="nofollow noreferrer" title="Screenshot of the Blender Preferences pane with Add-ons selected"><img src="https://i.sstatic.net/XZyib.png" alt="Screenshot of the Blender Preferences pane with Add-ons selected" title="Screenshot of the Blender Preferences pane with Add-ons selected" /></a></p>
<p>Go to <strong>Edit</strong> &gt; <strong>Preferences</strong> &gt; <strong>Add-ons</strong>.</p>
<p>Select the <strong>Mesh: 3D Toolbox</strong> plugin and install it.</p>
<p>Restart Blender.</p>
<p><a href="https://i.sstatic.net/gMBAs.png" rel="nofollow noreferrer" title="Screenshot of an import STL with the '3D Print' tab menu open"><img src="https://i.sstatic.net/gMBAs.png" alt="Screenshot of an import STL with the '3D Print' tab menu open" title="Screenshot of an import STL with the '3D Print' tab menu open" /></a></p>
<p>Import your STL (<strong>File</strong> &gt; <strong>Import</strong> &gt; <strong>STL</strong>). Press <kbd>N</kbd> to bring up the sidebar if not already visible, find the <strong>3D Print</strong> tab and select it, and open the <strong>Clean Up</strong> subsection.
Select your model in the main view (left-click it so it has an orange outline) and click <strong>Make Manifold</strong>.</p>
<p>The process may take a while, and Blender will be unresponsive throughout. After it completes, you'll see a message on the bottom: &quot;Modified:&quot; and some numbers of elements fixed. Repeat <strong>Make Manifold</strong> until &quot;Modified:&quot; shows only zeros.</p>
<p><a href="https://i.sstatic.net/dXJOl.png" rel="nofollow noreferrer" title="Screenshot of the 'Modified:' message at the bottom of the window showing the number of repaired elements"><img src="https://i.sstatic.net/dXJOl.png" alt="Screenshot of the 'Modified:' message at the bottom of the window showing the number of repaired elements" title="Screenshot of the 'Modified:' message at the bottom of the window showing the number of repaired elements" /></a></p>
<p>Make sure the repaired mesh is selected (orange outline). Pick <strong>File</strong> &gt; <strong>Export</strong> &gt; <strong>STL</strong>, and make sure you check <strong>Selection only</strong> then save the fixed mesh.</p>
<p><a href="https://i.sstatic.net/U1TQK.png" rel="nofollow noreferrer" title="Screenshot of the File Export dialog box with the 'Selection only' option selected"><img src="https://i.sstatic.net/U1TQK.png" alt="Screenshot of the File Export dialog box with the 'Selection only' option selected" title="Screenshot of the File Export dialog box with the 'Selection only' option selected" /></a></p>
<p>As of now, this is the easiest, most comprehensive, and most successful auto-repair option for meshes. That's not to say it's extremely successful—if the mesh is a hot mess, it may not help, it may even make things worse. In that case, you're up for a manual repair—you may need to look into more advanced repair tips, like from CG Boost's YouTube video <a href="https://www.youtube.com/watch?v=DAdYQ4xpNo0&amp;lc=UgyNDx-3-waxKw8RfkR4AaABAg" rel="nofollow noreferrer">&quot;How to Solve Common Sculpting Problems in Blender&quot;</a>.</p>

CC BY-SA 4.0
2023-09-25T11:58:24.380Z
2023-09-25T14:54:20.493Z
2023-09-25T14:54:20.493Z
SF.
<p>I use Elegoo Cura.</p>
<p>The blade and other parts of my print do not get sliced, and I don't know how to fix it</p>
<p>This is what is meant to be printed:</p>
<p><a href="https://i.sstatic.net/d5OAA.png" rel="nofollow noreferrer" title="This is what is meant to be printed"><img src="https://i.sstatic.net/d5OAA.png" alt="This is what is meant to be printed" title="This is what is meant to be printed" /></a></p>
<p>And this is what the print looks like, with the holes inverted, handle gone and the entire blade gone:</p>
<p><a href="https://i.sstatic.net/XavzQ.png" rel="nofollow noreferrer" title="This is what the print looks like"><img src="https://i.sstatic.net/XavzQ.png" alt="This is what the print looks like" title="This is what the print looks like" /></a></p>
<p>Appreciate any help.</p>

CC BY-SA 4.0
2023-08-23T05:08:24.653Z
Cura is terrible. The option "Print Thin Walls", which is disabled by default for some reason, should help though.
towe
CC BY-SA 4.0
2023-08-23T10:09:29.183Z
@towe no? that's inverted surface error
Trish
<elegoo-neptune-3>
How come certain parts of my model don't print?
twitchsmh
# How come certain parts of my model don't print?

(Asked by: username_0 on 2023-08-22)

I use Elegoo Cura.

The blade and other parts of my print do not get sliced, and I don't know how to fix it

This is what is meant to be printed:

[![This is what is meant to be printed](https://i.sstatic.net/d5OAA.png "This is what is meant to be printed")](https://i.sstatic.net/d5OAA.png "This is what is meant to be printed")

And this is what the print looks like, with the holes inverted, handle gone and the entire blade gone:

[![This is what the print looks like](https://i.sstatic.net/XavzQ.png "This is what the print looks like")](https://i.sstatic.net/XavzQ.png "This is what the print looks like")

Appreciate any help.

**Tags:** elegoo-neptune-3
> **Comments:**
> **username_1**: Cura is terrible. The option "Print Thin Walls", which is disabled by default for some reason, should help though.  
> **username_2**: @towe no? that's inverted surface error  

---

## 2 answers

### Answer by username_2 on 2023-08-23. Score: 1

The model has surfaces that are inverted. This is most notable with how the hole in the grip is turned into a cylinder, or the cutout in the blade being turned into a block.

To fix this, you need to fix the model.

> **Comments:**
> **username_0**: I downloaded it from Cults3D and I have no idea how, I will try to find another model.  

---

### Answer by username_3 on 2023-09-25. Score: 0

Bad model, as Trish says. Now onto how to fix it.

Install [Blender](https://www.blender.org/) and open it.

[![Screenshot of the Blender Preferences pane with Add-ons selected](https://i.sstatic.net/XZyib.png "Screenshot of the Blender Preferences pane with Add-ons selected")](https://i.sstatic.net/XZyib.png "Screenshot of the Blender Preferences pane with Add-ons selected")

Go to **Edit** > **Preferences** > **Add-ons**.

Select the **Mesh: 3D Toolbox** plugin and install it.

Restart Blender.

[![Screenshot of an import STL with the '3D Print' tab menu open](https://i.sstatic.net/gMBAs.png "Screenshot of an import STL with the '3D Print' tab menu open")](https://i.sstatic.net/gMBAs.png "Screenshot of an import STL with the '3D Print' tab menu open")

Import your STL (**File** > **Import** > **STL**). Press `N` to bring up the sidebar if not already visible, find the **3D Print** tab and select it, and open the **Clean Up** subsection.
Select your model in the main view (left-click it so it has an orange outline) and click **Make Manifold**.

The process may take a while, and Blender will be unresponsive throughout. After it completes, you'll see a message on the bottom: "Modified:" and some numbers of elements fixed. Repeat **Make Manifold** until "Modified:" shows only zeros.

[![Screenshot of the 'Modified:' message at the bottom of the window showing the number of repaired elements](https://i.sstatic.net/dXJOl.png "Screenshot of the 'Modified:' message at the bottom of the window showing the number of repaired elements")](https://i.sstatic.net/dXJOl.png "Screenshot of the 'Modified:' message at the bottom of the window showing the number of repaired elements")

Make sure the repaired mesh is selected (orange outline). Pick **File** > **Export** > **STL**, and make sure you check **Selection only** then save the fixed mesh.

[![Screenshot of the File Export dialog box with the 'Selection only' option selected](https://i.sstatic.net/U1TQK.png "Screenshot of the File Export dialog box with the 'Selection only' option selected")](https://i.sstatic.net/U1TQK.png "Screenshot of the File Export dialog box with the 'Selection only' option selected")

As of now, this is the easiest, most comprehensive, and most successful auto-repair option for meshes. That's not to say it's extremely successful—if the mesh is a hot mess, it may not help, it may even make things worse. In that case, you're up for a manual repair—you may need to look into more advanced repair tips, like from CG Boost's YouTube video ["How to Solve Common Sculpting Problems in Blender"](https://www.youtube.com/watch?v=DAdYQ4xpNo0&lc=UgyNDx-3-waxKw8RfkR4AaABAg).


---

