<p>I've found <strong>a</strong> way to do this, which I'll document here in case it helps someone else in the future.</p>
<ul>
<li>Export your parts as a single STEP file</li>
<li>Import that STEP file into PrusaSlicer</li>
<li>Set <strong>Print Settings &gt; Multiple Extruders &gt; Advanced &gt; Interface shells</strong>
<ul>
<li>(You need to be in <strong>Expert</strong> mode to see this option)</li>
</ul>
</li>
</ul>
<p><a href="https://i.sstatic.net/w2icK.jpg" rel="nofollow noreferrer" title="Screenshot of PrusaSlicer 2.7.0 showing the Interface Shells option"><img src="https://i.sstatic.net/w2icK.jpg" alt="Screenshot of PrusaSlicer 2.7.0 showing the Interface Shells option" title="Screenshot of PrusaSlicer 2.7.0 showing the Interface Shells option" /></a></p>
<p>The STEP file adds the internal walls, and this <strong>interface shells</strong> option adds the internal <strong>top and bottom</strong> layers I was missing:</p>
<p><a href="https://i.sstatic.net/NtA1r.jpg" rel="nofollow noreferrer" title="Screenshot of PrusaSlicer 2.7.0 showing sliced preview of a two-part print where interior layers / floors can be seen"><img src="https://i.sstatic.net/NtA1r.jpg" alt="Screenshot of PrusaSlicer 2.7.0 showing sliced preview of a two-part print where interior layers / floors can be seen" title="Screenshot of PrusaSlicer 2.7.0 showing sliced preview of a two-part print where interior layers / floors can be seen" /></a></p>

CC BY-SA 4.0
2023-12-08T17:05:43.213Z
2023-12-09T04:43:13.943Z
2023-12-09T04:43:13.943Z
RobM
<p>Despite how featureless the STL mesh looks when imported, all the data is there and you can split it to parts using the right click menu. I feel silly for now having spotted this before .</p>
<p><a href="https://i.sstatic.net/r60vY.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/r60vY.jpg" alt="PrusaSlicer 2.7.1 showing a featureless cube with a right click menu where &quot;Split &gt; To Parts&quot; has been selected" /></a></p>
<p>The result is exactly as I had hoped:</p>
<p><a href="https://i.sstatic.net/OJKpW.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/OJKpW.jpg" alt="PrusaSlicer 2.7.1 sliced view showing a two colour print and an object with two parts in the object list" /></a></p>
<p>My take away is that PrusaSlicer <em>does not</em> always prompt you to split your important mesh into multiple parts; so its always worth attempting to split to parts using the menu after import.</p>

CC BY-SA 4.0
2023-12-27T12:28:18.190Z
2023-12-27T12:28:18.190Z
RobM
<p>How do you import a multi-part object into PrusaSlicer without losing the position of the parts? For example, I want to print a two-material interlocking structure like this:</p>
<p><a href="https://i.sstatic.net/UC7Iy.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/UC7Iy.png" alt="Two-part object with interlocking dovetails" /></a></p>
<p>I've tried exporting this from my CAD software (OnShape) as a mesh (STL or OBJ) but when I import it into PrusaSlicer (v2.7.0) the result is either a single object with no internal walls:</p>
<p><a href="https://i.sstatic.net/yUPIu.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/yUPIu.png" alt="Screenshot of PrusaSlicer 2.7.0 showing a single featureless cube model" /></a></p>
<p>or (3MF) two objects placed on the build plate individually, so they no longer interlock:</p>
<p><a href="https://i.sstatic.net/FpLnH.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/FpLnH.jpg" alt="Screenshot of PrusaSlicer 2.7.0 where the two parts have been placed onto the build plate individually" /></a></p>
<p>If I use a STEP file it at least preserves the position of the parts within a single object, and there are some internal walls, but no internal top and bottom layers which I want for structural reasons (in this case the dovetail will simply crush in the XY plane if the part is tensioned in the Z axis):</p>
<p><a href="https://i.sstatic.net/hE73u.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/hE73u.jpg" alt="Screenshot of PrusaSlicer showing a sliced preview of a single object with two parts" /></a></p>
<p>What's a good way to import multiple parts and have them &quot;print in place&quot;, like they were in the original design?</p>

<slicing><prusaslicer><multi-material>
PrusaSlicer: How do I preserve the location of (interlocking) parts in a muliti-part model exported from OnShape / Blender?
RobM
# PrusaSlicer: How do I preserve the location of (interlocking) parts in a muliti-part model exported from OnShape / Blender?

(Asked by: username_0 on 2023-12-08)

How do you import a multi-part object into PrusaSlicer without losing the position of the parts? For example, I want to print a two-material interlocking structure like this:

[![Two-part object with interlocking dovetails](https://i.sstatic.net/UC7Iy.png)](https://i.sstatic.net/UC7Iy.png)

I've tried exporting this from my CAD software (OnShape) as a mesh (STL or OBJ) but when I import it into PrusaSlicer (v2.7.0) the result is either a single object with no internal walls:

[![Screenshot of PrusaSlicer 2.7.0 showing a single featureless cube model](https://i.sstatic.net/yUPIu.png)](https://i.sstatic.net/yUPIu.png)

or (3MF) two objects placed on the build plate individually, so they no longer interlock:

[![Screenshot of PrusaSlicer 2.7.0 where the two parts have been placed onto the build plate individually](https://i.sstatic.net/FpLnH.jpg)](https://i.sstatic.net/FpLnH.jpg)

If I use a STEP file it at least preserves the position of the parts within a single object, and there are some internal walls, but no internal top and bottom layers which I want for structural reasons (in this case the dovetail will simply crush in the XY plane if the part is tensioned in the Z axis):

[![Screenshot of PrusaSlicer showing a sliced preview of a single object with two parts](https://i.sstatic.net/hE73u.jpg)](https://i.sstatic.net/hE73u.jpg)

What's a good way to import multiple parts and have them "print in place", like they were in the original design?

**Tags:** slicing, prusaslicer, multi-material

---

## 2 answers

### Answer by username_0 on 2023-12-08. Score: 3

I've found **a** way to do this, which I'll document here in case it helps someone else in the future.

* Export your parts as a single STEP file
* Import that STEP file into PrusaSlicer
* Set **Print Settings > Multiple Extruders > Advanced > Interface shells**
  + (You need to be in **Expert** mode to see this option)

[![Screenshot of PrusaSlicer 2.7.0 showing the Interface Shells option](https://i.sstatic.net/w2icK.jpg "Screenshot of PrusaSlicer 2.7.0 showing the Interface Shells option")](https://i.sstatic.net/w2icK.jpg "Screenshot of PrusaSlicer 2.7.0 showing the Interface Shells option")

The STEP file adds the internal walls, and this **interface shells** option adds the internal **top and bottom** layers I was missing:

[![Screenshot of PrusaSlicer 2.7.0 showing sliced preview of a two-part print where interior layers / floors can be seen](https://i.sstatic.net/NtA1r.jpg "Screenshot of PrusaSlicer 2.7.0 showing sliced preview of a two-part print where interior layers / floors can be seen")](https://i.sstatic.net/NtA1r.jpg "Screenshot of PrusaSlicer 2.7.0 showing sliced preview of a two-part print where interior layers / floors can be seen")


---

### Answer by username_0 on 2023-12-27. Score: 0

Despite how featureless the STL mesh looks when imported, all the data is there and you can split it to parts using the right click menu. I feel silly for now having spotted this before .

[![PrusaSlicer 2.7.1 showing a featureless cube with a right click menu where ](https://i.sstatic.net/r60vY.jpg) To Parts" has been selected" />](https://i.sstatic.net/r60vY.jpg)

The result is exactly as I had hoped:

[![PrusaSlicer 2.7.1 sliced view showing a two colour print and an object with two parts in the object list](https://i.sstatic.net/OJKpW.jpg)](https://i.sstatic.net/OJKpW.jpg)

My take away is that PrusaSlicer *does not* always prompt you to split your important mesh into multiple parts; so its always worth attempting to split to parts using the menu after import.


---

