Before You Start Printing
A few important checks can save hours of printing and a lot of filament.
1. Can BrickForge make every set completely print-ready?
Not always. BrickForge automatically prepares files for the set you request. It does not rely on a catalogue of complete set packages prepared manually in advance.
How a set download is generated
When you enter a set number, BrickForge looks up its publicly available parts list, including the part numbers, quantities and colors. It then finds the individual part models in the open, community-built LDraw library.
LDraw supplies the source geometry. BrickForge converts the available models into STL files, attempts to repair the geometry, and organizes the results by color. It packages the files, an Excel parts list and 3MF projects into a ZIP download for you to check and prepare in your slicer.
Why can a set have missing parts?
A set appearing in the parts database does not mean that a 3D model exists for every part it contains. If a required model is unavailable or cannot be converted, the part is marked as missing in the Excel workbook. Supporting an additional part can therefore help every set that uses it.
Some models come from the unofficial LDraw library and are still awaiting review. These are marked in the Excel Notes column so you can give them extra attention. All generated models should be inspected before printing, including their orientation, dimensions and fit.
2. What should I check before printing?
After your set has been processed, first open the Excel workbook included in the ZIP archive. It provides an overview of the result and helps you confirm whether all required parts were found.
The Parts sheet
The first sheet, named Parts, contains the complete parts list, including the required quantities and colors.
- Green part-number cells indicate parts that BrickForge successfully found and prepared.
- Red part-number cells indicate parts that could not be found or converted.
- Some parts may be automatically replaced with compatible alternatives.
The original inventory may specify a printed part, a decorated version, or a part number containing a special suffix. If that exact model is unavailable but a geometrically identical undecorated version exists, BrickForge may use the equivalent plain part instead.
The printed decoration itself is not transferred to the generated model. Only the available geometry is used. Any automatic replacement is shown in the Replace column.
The Unique Parts sheet
The second sheet, named Unique Parts, lists each distinct part only once, regardless of how many copies or colors are required.
The part numbers on this sheet link to the corresponding Rebrickable part pages, where you can inspect each part. Green rows are found, red rows are missing, and yellow rows indicate an automatic replacement. The Status and Replacement columns show the same information in text.
What if some parts are missing?
A missing part does not necessarily mean that the entire set cannot be printed. You can report the part number through BrickForge’s Report a Part page. We will investigate it and, when possible, try to add support for it.
You can also search for a suitable model yourself. Always check the model’s dimensions, license and printability before using it.
After finding a missing model, you do not need to process the entire set again. Create a separate project in Bambu Studio or Orca Slicer, import the model, set the required quantity, and assign the appropriate color using the Excel workbook.
3. What should I do after opening a 3MF project?
Completed set conversions include separate multi-plate 3MF projects for Bambu Studio and Orca Slicer.
Each 3MF file can contain up to 360 parts, distributed across as many as nine build plates, with a maximum of 40 parts per plate. BrickForge initially groups parts by color: one build plate represents one color.
BrickForge does not perform the final print preparation for every model. It does not:
- determine the best printing orientation for every part;
- create an optimized physical arrangement on each build plate;
- determine exactly where supports are required;
- guarantee that every source model was converted without geometry problems.
Arrange the parts
Review every build plate and arrange the parts in a way that suits your printer. The BrickForge layout is an organized starting point, not a final arrangement that must be printed exactly as provided.
You can move parts, remove some and print them later, create additional plates, divide a large plate into several smaller ones, or change the plate order.
Check colors after moving parts
If you move parts between plates or create a new plate, the slicer may not preserve the intended color assignment. You may need to select the moved parts and assign the correct filament again.
Check orientation
Some parts may not be placed in the best orientation for FDM printing. Inspect every part and rotate it when necessary. Consider surface quality, overhangs, layer direction, strength and the amount of support material required.
Check supports
Select Slice Plate in your slicer. Bambu Studio or Orca Slicer may warn you about overhangs or areas that could require supports. Find the affected parts, inspect them, and enable or add supports when necessary.
A lack of warnings does not guarantee that every part has the ideal orientation or support configuration.
Inspect the models
Quickly inspect every build plate and look for parts with clearly damaged, incomplete, distorted or unusual geometry. The slicer may identify a problematic model during slicing. Do not print a part that appears visibly broken or produces slicing errors.
Found a broken part?
Use Report a Part to send us the part number and a description of the problem. We will investigate the model and, when possible, try to repair it or find a suitable replacement.
4. How do I choose the correct colors?
For every part, the Parts sheet shows the original part color, a recommended filament color and an alternative filament color.
Choose the closest match from the filaments available to you. BrickForge’s suggestions are recommendations, not exact requirements. Colors vary between manufacturers, and an exact match may not be available.
Some parts may be completely hidden inside the finished model. If a part will not be visible, using the exact original color may not be necessary.
5. How many parts should I print at once?
A BrickForge build plate may contain up to 40 parts, but that does not mean you must print all of them simultaneously. The plate layout is primarily a convenient way to organize the files.
You can divide a plate into smaller print jobs, move some parts to a new plate, or remove parts temporarily and print them later.
If this is your first time printing parts generated by BrickForge, begin with a small number of parts and confirm that they print correctly before starting a large batch.
Remember to verify the assigned colors whenever you move parts between build plates.
6. Am I ready to press Print? 😄
Not quite. Before committing to an entire set, we strongly recommend performing a small test print.
You do not need to process a complete set. Open the Single Part tab on BrickForge and download two or three different but compatible parts.
Print them at 100% scale first and test how they connect to one another. Do not change the scale of only one part, because independently scaled parts will no longer fit together correctly.
Why is a test print important?
Physical interlocking parts require very small manufacturing tolerances to connect correctly. LDraw models are primarily intended to represent parts digitally. They are not factory manufacturing CAD files containing production tolerances specifically designed for FDM printing.
Results also depend on your printer, nozzle diameter, calibration, filament, temperature, layer height and slicer settings. The same model can therefore produce slightly different results on different printers.
Test the connection
The parts should not require excessive force, but they should not fall apart easily or have excessive movement.
A slightly loose connection may still be acceptable. For display models that will not be disassembled, some users apply a small amount of glue during final assembly.
If the fit is clearly too tight or too loose, adjust your printer or slicer settings and repeat the test before printing the complete set.
Which settings should I use?
There is no universal profile that works perfectly for every printer and filament. You will need to find suitable settings for your specific printer, filament, nozzle and slicer.
Spending a small amount of time and material on test parts can prevent much larger failed prints later.
Still having trouble?
BrickForge is continually being improved. If you find a missing or damaged part, report its number and describe the issue. For general questions or problems not covered in this guide, use the Contact page. We cannot promise that every issue can be resolved, but we will investigate it and improve BrickForge whenever possible.