<p>STL models as exported by software often include their origin in the origin of the design software. However, when using software to fix modeling errors, those origins are not always retained and thus when importing them into a different software their <em>center of mass</em> is taken as the new point of reference.</p>
<p>Slicers are notorious in that they ignore the included origin. Even <em>if</em> models contain an origin that would, when imported into 3D design environments result in the items lining up correctly, the slicing software will simply not care and take a <em>lowest point in the projected center of the object</em> as the coordinate for the item, as this is what is relevant for positioning in the software.</p>
<p>To mitigate that problem, it is best to export models that need to be <em>joined</em> after processing a boolean union on them.</p>

CC BY-SA 4.0
2022-05-04T11:12:32.517Z
2022-05-04T14:10:26.497Z
2022-05-04T14:10:26.497Z
Trish
<p>I came across this thread as I was facing the exact same issue. I am also using 3D Builder to repair my STLs before 3D printing them.</p>
<p>The previous answers were however not sufficient (for me) so I went on a trial-and-error spree to determine what was happening, I think I found the answer! (hope that you can still use it!)</p>
<p>An STL file has certain characteristics regarding its location (origin point): X, Y, Z and rotational for the same axes. When you import one or multiple STL files in the 3D builder, it keeps all of these origin points except for the z axis, it automatically places the model/models on the bed so that the lowest point in your (combined) model has a point of Z = 0.</p>
<p>To ensure that all your parts have the same &quot;origin point&quot; you should import the model all at once and then remove all parts except for one. Then, auto-repair it and save it under a certain name.</p>
<p>For example: You have a combined file consisting of three parts.</p>
<ul>
<li>Import parts 1-3 → remove parts 2 and 3 → repair remaining part 1 → save as part 1</li>
<li>Import parts 1-3 → remove parts 1 and 3 → repair remaining part 2 → save as part 2</li>
<li>Import parts 1-3 → remove parts 1 and 2 → repair remaining part 3 → save as part 3</li>
</ul>
<p>You now have a repaired model for all parts and their origin points should all be the same!</p>

CC BY-SA 4.0
2023-11-11T11:03:09.067Z
2023-11-11T20:57:26.793Z
2023-11-11T20:57:26.793Z
Mark van Weringh
<p>It has moved the object to the ground as close as it could. This is generally best for 3D printing separate objects.</p>
<p>If you need them together, you can reposition them, or combine them.</p>
<p>Alternatively, change the 'Collision' and 'Intersect' settings until you get what you want.</p>

CC BY-SA 4.0
2022-05-03T05:34:29.493Z
Thanks, so I guess even the position was shifted, it will not affect the printing result.
brian661
CC BY-SA 4.0
2022-05-03T02:52:48.227Z
2023-01-02T13:14:02.667Z
2023-01-02T13:14:02.667Z
Kilisi
<p>I build and export my model using ZBrush and as STL files.<br />
To fix the mesh for 3D print, I try to use 3D Builder which can automatically repair my parts.<br />
As it saves as a single file, if I import all parts at once,<br />
I import the files one by one, repair them, then save them as a new file.<br />
After all the parts were repaired, I import all parts to see the result<br />
but find some repaired parts' positions shifted.<br />
How should I handle these issues?</p>
<p><a href="https://i.sstatic.net/01xRd.png" rel="nofollow noreferrer" title="Rendering of 3D model with parts shifted from original position"><img src="https://i.sstatic.net/01xRd.png" alt="Rendering of 3D model with parts shifted from original position" title="Rendering of 3D model with parts shifted from original position" /></a></p>

CC BY-SA 4.0
2022-05-03T01:24:51.050Z
Why not just move them back where you want them?
Kilisi
CC BY-SA 4.0
2022-05-03T05:33:26.367Z
@Kilisi because I break into parts using boolean inside zbrush, if i move by myself, there will definitely have some tiny overlapping
brian661
<repair><print-preparation>
3D Builder: position shifted after auto repair
brian661
# 3D Builder: position shifted after auto repair

(Asked by: username_0 on 2022-05-02)

I build and export my model using ZBrush and as STL files.  
To fix the mesh for 3D print, I try to use 3D Builder which can automatically repair my parts.  
As it saves as a single file, if I import all parts at once,  
I import the files one by one, repair them, then save them as a new file.  
After all the parts were repaired, I import all parts to see the result  
but find some repaired parts' positions shifted.  
How should I handle these issues?

[![Rendering of 3D model with parts shifted from original position](https://i.sstatic.net/01xRd.png "Rendering of 3D model with parts shifted from original position")](https://i.sstatic.net/01xRd.png "Rendering of 3D model with parts shifted from original position")

**Tags:** repair, print-preparation
> **Comments:**
> **username_1**: Why not just move them back where you want them?  
> **username_0**: @Kilisi because I break into parts using boolean inside zbrush, if i move by myself, there will definitely have some tiny overlapping  

---

## 3 answers

### Answer by username_2 on 2022-05-04. Score: 2 | Accepted answer

STL models as exported by software often include their origin in the origin of the design software. However, when using software to fix modeling errors, those origins are not always retained and thus when importing them into a different software their *center of mass* is taken as the new point of reference.

Slicers are notorious in that they ignore the included origin. Even *if* models contain an origin that would, when imported into 3D design environments result in the items lining up correctly, the slicing software will simply not care and take a *lowest point in the projected center of the object* as the coordinate for the item, as this is what is relevant for positioning in the software.

To mitigate that problem, it is best to export models that need to be *joined* after processing a boolean union on them.


---

### Answer by username_3 on 2023-11-11. Score: 2

I came across this thread as I was facing the exact same issue. I am also using 3D Builder to repair my STLs before 3D printing them.

The previous answers were however not sufficient (for me) so I went on a trial-and-error spree to determine what was happening, I think I found the answer! (hope that you can still use it!)

An STL file has certain characteristics regarding its location (origin point): X, Y, Z and rotational for the same axes. When you import one or multiple STL files in the 3D builder, it keeps all of these origin points except for the z axis, it automatically places the model/models on the bed so that the lowest point in your (combined) model has a point of Z = 0.

To ensure that all your parts have the same "origin point" you should import the model all at once and then remove all parts except for one. Then, auto-repair it and save it under a certain name.

For example: You have a combined file consisting of three parts.

* Import parts 1-3 → remove parts 2 and 3 → repair remaining part 1 → save as part 1
* Import parts 1-3 → remove parts 1 and 3 → repair remaining part 2 → save as part 2
* Import parts 1-3 → remove parts 1 and 2 → repair remaining part 3 → save as part 3

You now have a repaired model for all parts and their origin points should all be the same!


---

### Answer by username_1 on 2022-05-03. Score: 1

It has moved the object to the ground as close as it could. This is generally best for 3D printing separate objects.

If you need them together, you can reposition them, or combine them.

Alternatively, change the 'Collision' and 'Intersect' settings until you get what you want.

> **Comments:**
> **username_0**: Thanks, so I guess even the position was shifted, it will not affect the printing result.  

---

