<h1>The problem</h1>
<p>FDM printers slice models in STL or OBJ format. Neither of these formats can transmit properties like <em>Materials</em>: they consist <strong>fully</strong> of surface definitions.</p>
<h1>But... Multi-Material printing is a thing, yes?</h1>
<p>Yes, but Multi-material prints use a simple trick: a single STL object can contain <em>more</em> than one surface definition, and you can slice more than one STL at once. But since slicers usually can't separate these from one another, they usually load multiple STLs and define the materials for each differently. For example, <a href="https://www.thingiverse.com/thing:3197896" rel="nofollow noreferrer">Adalinda</a> has 4 different STLs, some containing multiple chunks of material, each STL corresponding to one printed color. And <a href="https://youtu.be/MnOWX4Ujtv8?list=TLPQMDIwMjIwMjHXGYYAQZ7qbw" rel="nofollow noreferrer">in this video Joel</a> explains how printing that way works for an older version of the MMU.</p>
<p>So, to print the &quot;cubes&quot; in a different material, you'd need to have two STLs: The grid as one export, and the cubes as another. Then the <strong>Rest</strong> is slicing.</p>
<h1>Way around?</h1>
<p>Now, you might not have a Multi-Material Printer? Then you might want to design your item in parts that snap into place or have an interference fit. For example, you might print a plate with all the cubes on one side, and a grid that has a relief on the back where the plate goes. Then you print two times with different materials and push the cube part into the grate, some glue in between, and voila! It looks like one print from the surface. With a clamshell design, you might even completely hide the existence of the carrier plate - by having two grates that surround a hollow cavity for the cube-plate, and the cube plate pushes out into either of the clamshells.</p>

CC BY-SA 4.0
2021-02-03T21:03:35.917Z
Thank you guys! I figured out the solution, I will share in the post shortly.
Monika
CC BY-SA 4.0
2021-02-02T15:39:07.063Z
2021-02-02T15:39:07.063Z
Trish
<p>If you are asking for print then it is yes with FDM (fused deposition modeling) with multiple extrusion you can fill with different material easily. But if you are trying to change the material in your digital design then you need to work on every hole in the array, especially with FreeCAD. If you find any, please update here.</p>

CC BY-SA 4.0
2021-01-15T17:12:54.423Z
2021-01-15T22:52:50.787Z
2021-01-15T22:52:50.787Z
Kosireddy Harshavardhan Reddy
<p>I have an array with holes that I have to fill with different materials. My question is there is an easy way to fill them directly? I tried array, array draft and it is annoying to adjust them. In Blender, it easy to select the vertices and fill. Maybe it is a stupid question, but I am not really an expert.</p>
<p><a href="https://i.sstatic.net/7VwUW.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/7VwUW.png" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2021-01-16T22:58:00.090Z
Have you tried sketching a new object in a hole and arraying that object? That way you can have separate FreeCAD bodies to export for printing
JPeroutek
<3d-models><freecad>
How to fill these squares easily
Monika
# How to fill these squares easily

(Asked by: username_0 on 2021-01-15)

I have an array with holes that I have to fill with different materials. My question is there is an easy way to fill them directly? I tried array, array draft and it is annoying to adjust them. In Blender, it easy to select the vertices and fill. Maybe it is a stupid question, but I am not really an expert.

[![enter image description here](https://i.sstatic.net/7VwUW.png)](https://i.sstatic.net/7VwUW.png)

**Tags:** 3d-models, freecad
> **Comments:**
> **username_1**: Have you tried sketching a new object in a hole and arraying that object? That way you can have separate FreeCAD bodies to export for printing  

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## 2 answers

### Answer by username_2 on 2021-02-02. Score: 1

# The problem

FDM printers slice models in STL or OBJ format. Neither of these formats can transmit properties like *Materials*: they consist **fully** of surface definitions.

# But... Multi-Material printing is a thing, yes?

Yes, but Multi-material prints use a simple trick: a single STL object can contain *more* than one surface definition, and you can slice more than one STL at once. But since slicers usually can't separate these from one another, they usually load multiple STLs and define the materials for each differently. For example, [Adalinda](https://www.thingiverse.com/thing:3197896) has 4 different STLs, some containing multiple chunks of material, each STL corresponding to one printed color. And [in this video Joel](https://youtu.be/MnOWX4Ujtv8?list=TLPQMDIwMjIwMjHXGYYAQZ7qbw) explains how printing that way works for an older version of the MMU.

So, to print the "cubes" in a different material, you'd need to have two STLs: The grid as one export, and the cubes as another. Then the **Rest** is slicing.

# Way around?

Now, you might not have a Multi-Material Printer? Then you might want to design your item in parts that snap into place or have an interference fit. For example, you might print a plate with all the cubes on one side, and a grid that has a relief on the back where the plate goes. Then you print two times with different materials and push the cube part into the grate, some glue in between, and voila! It looks like one print from the surface. With a clamshell design, you might even completely hide the existence of the carrier plate - by having two grates that surround a hollow cavity for the cube-plate, and the cube plate pushes out into either of the clamshells.

> **Comments:**
> **username_0**: Thank you guys! I figured out the solution, I will share in the post shortly.  

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### Answer by username_3 on 2021-01-15. Score: 0

If you are asking for print then it is yes with FDM (fused deposition modeling) with multiple extrusion you can fill with different material easily. But if you are trying to change the material in your digital design then you need to work on every hole in the array, especially with FreeCAD. If you find any, please update here.


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