{"id":809,"date":"2024-06-13T00:58:27","date_gmt":"2024-06-13T00:58:27","guid":{"rendered":"http:\/\/tgaw.com\/wp\/?p=809"},"modified":"2025-12-28T23:51:46","modified_gmt":"2025-12-28T23:51:46","slug":"coding-custom-infills-for-the-slic3r-based-slicers-prusaslicer-bambu-studio-etc","status":"publish","type":"post","link":"https:\/\/tgaw.com\/wp\/coding-custom-infills-for-the-slic3r-based-slicers-prusaslicer-bambu-studio-etc\/","title":{"rendered":"Coding Custom Infills for the Slic3r Based Slicers (PrusaSlicer, Bambu Studio, Orca, etc.)"},"content":{"rendered":"\r\n

Prusa Slicer and Bambu Studio are built over the Slic3r code base. In a meeting proceeding the 2023 East Coast RepRap Festival (ERRF), the board members made a joke about making our own ERRF infill pattern. It got me wondering, what would be involved with making a custom infill? I downloaded the PrusaSlicer code from GitHub<\/a> and it turned out and it is pretty do-able with the Visual Studio 2022 I already use for other projects.<\/p>\r\n\r\n\r\n\r\n

Here’s how I approached it. I’ve only done this in PrusaSlicer, but I believe the steps should be similar in other Slic3r-based slicers like Bambu Studio and Orca. I’ve done three infills now – the original ERRF, one for 3DPrintopia, and my favorite some tessellated hearts!<\/p>\r\n\r\n\r\n\r\n

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Heart Infill!<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

Note: Not everything in this giant post is going to apply to you, but the information is there for those who will find it handy. If you need a TL;DR, the most basic steps would be:<\/p>\r\n\r\n\r\n\r\n

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  1. Get the source code<\/a> on your development machine.<\/li>\r\n
  2. Plan out the “output points” for your pattern. This could be low-tech like graph paper<\/a> or you could use a tool like Blender<\/a>.<\/li>\r\n
  3. Update the code<\/a>. The impacted files would be:\r\n
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    1. libslic3r\\Fill\\FillPlanePath.cpp <\/strong>– Add your logic to define all your output points.<\/li>\r\n
    2. libslic3r\\Fill\\FillPlanePath.hpp<\/strong> – Add declarations for your new infill functions in FillPlanePath.cpp.<\/li>\r\n
    3. libslic3r\\Fill\\Fill.cpp<\/strong> – Add in a new case into the surface_fill.params.pattern switch statement.<\/li>\r\n
    4. libslic3r\\Fill\\FillBase.cpp<\/strong> – Add a new case into the new_from_type switch statement.<\/li>\r\n
    5. libslic3r\\PrintConfig.cpp<\/strong> – Add new values into:\r\n
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      1. s_keys_map_InfillPattern.<\/li>\r\n
      2. Fill pattern options in PrintConfigDef.<\/li>\r\n<\/ol>\r\n<\/li>\r\n
      3. libslic3r\\PrintConfig.hpp<\/strong> – Add a new value into the InfillPattern enum.<\/li>\r\n
      4. libslic3d\\PrintObject.cpp <\/strong>– Optional – you can add in a new case for determine_bridging_angle.<\/li>\r\n<\/ol>\r\n<\/li>\r\n
      5. Test your infill.<\/a><\/li>\r\n
      6. Print<\/a>!<\/li>\r\n<\/ol>\r\n\r\n\r\n\r\n

         <\/p>\r\n\r\n\r\n\r\n

        Getting and Building the Source Code<\/h2>\r\n\r\n\r\n\r\n

        I think for me, the longest step was getting the source code ready and initially compiled on my machine.You can get the source code of the slicer you want from GitHub:<\/p>\r\n\r\n\r\n\r\n

        PrusaSlicer Souce Code<\/a>
        Bambu Studio Source Code<\/a>
        Slic3r Source Code<\/a><\/p>\r\n\r\n\r\n\r\n

        Building On Your Development Machine<\/h3>\r\n\r\n\r\n\r\n

        The PrusaSlicer doc folder on GitHub<\/a> has “How to Build” instructions for Windows, Linux and MacOS. Like everything Prusa does, the documentation was thorough and helpful! I’m working on a Windows machine, so I used the “Building PrusaSlicer on Windows<\/a>” instructions. I think the instructions did a great job of highlighting the prerequisites and walking me through the process.<\/p>\r\n\r\n\r\n\r\n

        Planning The Infill<\/h2>\r\n\r\n\r\n\r\n

        The code is in C++ which I hadn’t worked with in over two decades<\/em>. Luckily, one can be rusty in C++ and still copy and paste! I started by looking through the infill code in the libslicer\\Fill directory. The FillPlanePath.cpp<\/strong> is where I ran across the Hilbert Curve<\/strong>. It was pretty much just making a large collection of points for the infill, like connect the dots. That meant I just needed logic to come up with my points. Once I make all my output points, all the existing code does the rest.<\/p>\r\n\r\n\r\n\r\n

        Planning with Graph Paper<\/h3>\r\n\r\n\r\n\r\n

        I decided on my points for the ERRF infill and the 3DPrintopia Infill in a decidedly low-tech way. I got out graph paper, I drew what I wanted and planned my points.<\/p>\r\n\r\n\r\n\r\n

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        Drawing my ERRF Infill<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

        Tip – One best practice I learned is if you are doing text and you want it readable from the top of your print, you’ll want to plot your points backwards (a mirror image of what you want). <\/em><\/strong><\/p>\r\n\r\n\r\n\r\n

        When you are planning your infill, think about it as one continuous line. This also means considering how you are going to start a brand new line of your pattern. You don’t want the printer to draw (or collide!) with lines that were already printed.<\/p>\r\n\r\n\r\n\r\n

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        An example of what you *don’t* want.<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

        You could address it like a typewriter where at the end of each line, you add in some points that get you back to the beginning for the next line. With the ERRF and 3DPrintopia text, that journey back to the start gave me an opportunity to refine my letters more. With a continuous path the R’s were pretty basic, but on my way back to start a new line, I could take a quick “detour” and draw some little holes in my R’s.<\/p>\r\n\r\n\r\n\r\n

        If you look again at my ERRF graph paper, you’ll see two sections of points. First, I have my points that draw my base letters which can be repeated as much as necessary.<\/p>\r\n\r\n\r\n\r\n

        \"ERRF\r\n
        ERRF Points – Initial Pass<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

        Then for the return back to the start of the beginning of the “page”, I have my points to fill in extra details for the letters to come.<\/p>\r\n\r\n\r\n\r\n

        \"ERRF\r\n
        ERRF Points – Return pass<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

         <\/p>\r\n\r\n\r\n\r\n

        I translated both of those to x\/y coordinates using the graph paper as a guide.<\/p>\r\n\r\n\r\n\r\n

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        Figuring out the coordinates to draw a single ERRF<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n
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        Coordinate points for my “connector” line for the ERRF Infill<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

        Planning The Infill (With Blender and Python)<\/h3>\r\n\r\n\r\n\r\n

        The heart infill, I expected to be more complicated and with more points, so I attacked that in a different way. In Blender, I used a Bezier Curve to draw my heart (with an Array modifier to give me an idea of how it would look with repetition). Once I was satisfied with the shape, I right clicked<\/strong> on it and chose Convert To<\/strong> -> Mesh. <\/strong><\/p>\r\n\r\n\r\n\r\n

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        Converting a curve to a mesh in Blender<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

        That converted my curve to vertices\/points. Instead of graph paper, I could then refer to Blender’s coordinate system to get my output points.<\/p>\r\n\r\n\r\n\r\n

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        Planning my output points using Blender’s coordinate system<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n

        The heart was a lot of points and it was going to be a wee tedious to grab the X and Y coordinate of all 106 vertices. In this case, I decided to speed up the process using a Python script. Under the Scripting<\/strong> tab, I ran the following code to not only get my coordinates, but write out the lines of C++ code I would ultimately need for the slicer (more later):<\/p>\r\n\r\n\r\n\r\n

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        The Python script in Blender to get the coordinates of all the vertices<\/figcaption>\r\n<\/figure>\r\n\r\n\r\n\r\n