Splitting Multicolor 3D Prints to Cut Filament Waste

Updated 14 November 2026 · Standard formula, shown below

This guide explains how splitting a large multicolor 3D print into separate parts can dramatically reduce filament waste—especially the purged material and color changes that occur with multi-extruder or single-nozzle setups. By printing each color region as its own object and gluing the pieces together, you avoid most of the waste generated by frequent filament swaps. You’ll learn the planning, slicing, and assembly steps, plus common mistakes and troubleshooting tips.

What You’ll Need

A 3D printer (any type that can print single-color parts)
Slicing software (e.g., Cura, PrusaSlicer, or similar)
3D modeling software (e.g., Tinkercad, Fusion 360, Blender) or a tool that can split STL files
CA glue (super glue) or epoxy for assembling parts
Sandpaper or a file for smoothing mating surfaces (optional)
Clamps or rubber bands to hold parts while glue dries (optional)

Step-by-Step

Identify the color regions. Open your 3D model in your slicer and look at the color scheme. Determine which parts of the model are a single color and could be printed separately. For example, a model with a red body and blue eyes could be split into a red body piece and two blue eye pieces.
Split the model in your 3D modeling software. Use a cutting tool to separate the model along the color boundaries. For simple splits, you can use a plane cut. For more complex shapes, you might need to use boolean operations or manually create separate parts. Ensure each part is a closed, watertight mesh.
Add alignment features (optional but recommended). To make assembly easier, add small pins, holes, or notches to the mating surfaces. For example, add a small cylinder on one part and a matching hole on the other. This ensures the parts align correctly when glued.
Export each part as its own STL file. Name them clearly, like body.stl and eyes.stl.
Slice each part individually. Open each STL in your slicer and set the filament color for that part. Print them one at a time. You’ll use only the colors needed for each part, so no waste from color changes.
Print each part. Use your normal print settings. Since each part is single-color, you can also optimize layer height or infill per part if needed.
Clean the mating surfaces. After printing, remove any brim or support material. Sand the surfaces that will be glued to ensure a flat, tight fit.
Test-fit the parts. Dry-fit the pieces together to check alignment. If they don’t fit, trim or sand as needed.
Glue the parts together. Apply a thin layer of CA glue or epoxy to one surface, press the parts together, and hold them with clamps or rubber bands for the time specified by the adhesive.
Finish the print. After the glue cures, you may want to fill any seams with filler or sand the joint for a smooth finish. Then paint or seal if desired.

Common Mistakes

Splitting along non-planar surfaces. If the split is not a flat plane, the parts may not fit together well. Use simple cuts or add alignment features.
Forgetting about wall thickness. When splitting, ensure each part has enough wall thickness to remain structurally sound. Thin walls may warp or break.
Not accounting for shrinkage. Different filament colors may shrink slightly differently. This is usually negligible, but for tight tolerances, test with a small print first.
Skipping alignment features. Without pins or notches, parts can shift when gluing, leading to misalignment.
Using too much glue. Excess glue can seep out and ruin the finish. Use a thin, even layer.

Tips

Use a slicer’s built-in split function. Some slicers like PrusaSlicer have a “Split to objects” feature that can cut a model along a plane. This is faster than modeling software for simple splits.
Print a test piece. Before splitting the full model, print a small test with the same split to check fit and alignment.
Optimize print orientation. Print each part in the orientation that minimizes supports and gives the best surface finish on the visible sides.
Use a brim or raft. For parts with small contact area, a brim helps with adhesion and reduces warping.
Consider using a multi-material printer with a purge tower. If you have a multi-extruder printer, splitting is still useful when the waste from purge towers is excessive.

Troubleshooting

Parts don’t fit together. Check for warping or elephant’s foot on the mating surfaces. Sand them down or reprint with a slight offset (e.g., add 0.1mm clearance).
Alignment is off. If you didn’t add pins, try adding them now by drilling small holes and inserting dowels. Or use a jig to hold parts in place while gluing.
Glue joint is weak. Ensure surfaces are clean and dry. Use a stronger adhesive like epoxy, or increase the contact area by adding a small flange.
Visible seam after assembly. Fill the seam with a filler (e.g., wood filler or epoxy putty), sand smooth, and paint over.
Warping during print. Use a heated bed, enclosure, or brim. Also, print the part with the largest flat surface on the bed.

Frequently Asked Questions

Does splitting always reduce waste? Yes, because you avoid the purged filament and color changes. However, you may add waste from supports or failed prints, so it’s not a 100% reduction, but typically significant.
Can I split a model that has interlocking parts? Yes, but you need to design the split so parts can be assembled. Sometimes you need to cut through interlocking geometry and then glue.
What if my model has more than two colors? Split into as many parts as needed. Each color becomes its own print.
How do I split a model without 3D modeling software? Use a slicer’s cut feature (e.g., PrusaSlicer’s “Cut” tool) or an online STL splitter. These tools are limited to plane cuts, but often sufficient.
Is the glued part as strong as a single print? The glue joint is usually weaker than the printed material, but with proper surface prep and a good adhesive, it can be strong enough for most decorative or light-duty parts.
Can I use a multi-material printer and still split? Yes, but the benefit is smaller. Multi-material printers still waste filament on purge towers and color changes, so splitting can reduce that waste.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.