<p>Some tools like Cura or Repetier Host have slicers that analyses and tell you if it is ok to print or not. Both of them allow rotations.</p>

CC BY-SA 3.0
2018-02-07T16:56:01.537Z
Cura's rotate tool has a "lay flat" function! I just had to manually get the rotation in the general direct and it was able to rotate it the rest of the way. Thanks!
Jared Deckard
CC BY-SA 3.0
2018-02-07T09:50:18.030Z
2018-02-07T09:50:18.030Z
Hola Soy Edu Feliz Navidad
<p>I have an STL that has a flat surface which should contact the build place when 3D printing. The model has an unknown rotation. How can I rotate the 3D model to be flush with the build plate?</p>

<p>I am very comfortable with OpenSCAD, and I can use it to rotate the STL if I know the correct angle. Is there a tool that will let me analyze a single face (triangle) of a model to determine it's normal? If I can even get the coordinates from 3 points from the desired face I can calculate the normal and use that to calculate the rotation vector.</p>

CC BY-SA 3.0
2018-02-06T05:01:21.917Z
I made a little bit of progress: Meshmixer's "Mesh Query" analysis tool allows me to select individual triangles. The "Triangle ID" it shows is a 0-based index to a "facet" of the STL file in ASCII mode. It looks like the normal of the 3 vertexes is already computed for me. I am going to have to do this several times, so if there is a better way I am open to suggestions.
Jared Deckard
CC BY-SA 3.0
2018-02-07T16:40:16.417Z
I needed to get something started on the printer so I just imported an STL into OpenSCAD and started guessing values for the rotation vector. Since I had a large flat surface, I was able to use orthogonal view and the static camera angles to align the model to each axis. It took about 6 passes using 2 decimals of precision to get it to the point that the slicer treated the bottom as a single layer. That took 5-10 minutes per STL. Doing this 6 times was pretty manageable. Much more and I definitely would have probably done the math and scripted the process.
Jared Deckard
<3d-models><software><file-formats><analysis><stl>
How can I rotate a 3D model to be parallel with the build plate?
Jared Deckard
# How can I rotate a 3D model to be parallel with the build plate?

(Asked by: username_0 on 2018-02-06)

I have an STL that has a flat surface which should contact the build place when 3D printing. The model has an unknown rotation. How can I rotate the 3D model to be flush with the build plate?

I am very comfortable with OpenSCAD, and I can use it to rotate the STL if I know the correct angle. Is there a tool that will let me analyze a single face (triangle) of a model to determine it's normal? If I can even get the coordinates from 3 points from the desired face I can calculate the normal and use that to calculate the rotation vector.

**Tags:** 3d-models, software, file-formats, analysis, stl
> **Comments:**
> **username_0**: I made a little bit of progress: Meshmixer's "Mesh Query" analysis tool allows me to select individual triangles. The "Triangle ID" it shows is a 0-based index to a "facet" of the STL file in ASCII mode. It looks like the normal of the 3 vertexes is already computed for me. I am going to have to do this several times, so if there is a better way I am open to suggestions.  
> **username_0**: I needed to get something started on the printer so I just imported an STL into OpenSCAD and started guessing values for the rotation vector. Since I had a large flat surface, I was able to use orthogonal view and the static camera angles to align the model to each axis. It took about 6 passes using 2 decimals of precision to get it to the point that the slicer treated the bottom as a single layer. That took 5-10 minutes per STL. Doing this 6 times was pretty manageable. Much more and I definitely would have probably done the math and scripted the process.  

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## 1 answers

### Answer by username_1 on 2018-02-07. Score: 1 | Accepted answer

Some tools like Cura or Repetier Host have slicers that analyses and tell you if it is ok to print or not. Both of them allow rotations.

> **Comments:**
> **username_0**: Cura's rotate tool has a "lay flat" function! I just had to manually get the rotation in the general direct and it was able to rotate it the rest of the way. Thanks!  

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