We tried the all-new Model Splitter and found it was exactly the kind of splitting tool we hadn't realized we needed.
This browser-based tool makes cutting models and adding custom seams incredibly easy. According to its official website, Model Splitter is currently in public beta, supports STL and 3MF files, and processes models locally.
Its "Auto Multi-Plane" tool calculates cut positions based on the printer's build volume, spacing them according to size rather than for aesthetically pleasing joints.
In our testing, its sculpting tools were hard to control precisely.
Splitting models for 3D printing usually doesn't require a dedicated app. Our guides on cutting models in Bambu Studio, PrusaSlicer, OrcaSlicer, and Cura have already covered this—slicer software can handle a lot of everyday splitting work and comes with built-in connectors for assembling the split parts.
Model Splitter offers a more precise way to define cut positions directly on the model surface, and it can automate the process with speed and efficiency that other tools can't match. It can also add shapes to a model and sculpt away a bit of material.
Instead of just placing a straight cutting plane, you can paint the area you want to separate, or draw a closed seam around it. This is especially appealing for organic models that cross beyond flat boundaries.
Of course, you could also go the Tinkercad route. Its familiar solids-plus-holes workflow lets you remove material with overlapping shapes, duplicate the model to keep both sides, and build your own alignment features. But Model Splitter packages this prep work into a dedicated splitting workflow: define the seam, choose connectors, adjust dimensions and clearance, and generate the parts. The advantage is less manual building—not that Tinkercad can't produce similar geometry.
A big advantage is automation. "Auto Multi-Plane" solves a different problem. Enter the printer's build volume, and the app calculates a set of cuts to make the model fit. In our test, it generated multiple planes at once, which could then be adjusted, while checking whether each part still fit. However, these cuts are spaced by size and won't automatically find the most visually pleasing joint between features.
Feedback is also a useful part of the experience. Model Splitter warns you when a cut may not be ideal. It flags disconnected parts, marks items in red for review, and explains why a certain cutting face can't fit the requested connector pins. This helps you distinguish between "the cut is done" and "there's actually enough material to place connectors during assembly."
Model Splitter is currently in public beta, supports STL and 3MF files, and according to its official website processes models locally in the browser. It also has boolean operations, basic shapes, mesh inspection, and sculpting tools.
To see how this combination works in practice, we tested a T. rex skeleton and a solid snowman below. The cutting tools impressed me the most. Sculpting on the test models wasn't very controllable, but when simple slice cuts aren't enough, this app is already a promising option.
01 First test: taking apart a dinosaur
The first test subject was a T. rex skeleton. Thin bones and disconnected features made it challenging, especially when adding connectors. We started with "Paint Cut," which lets you paint the entire area you want to separate. The controls were fine, but selecting the tail took time: you had to rotate the model and reach surfaces on the back side.
Switching to "Plane" mode was much faster. There's a handy feature here: when a plane intersects the model at multiple locations, you can click individual intersection loops to target that region, rather than cutting away everything the plane passes through.
After the tail was cut, Model Splitter gave detailed feedback. It identified two loose parts not connected to either main half and marked their locations in red. It also explained why the requested connector pins weren't added: the cutting face was too narrow.
This feedback is valuable. A successful cut doesn't mean every part is connected and assemblable, and the app points out these limitations clearly.
Drawing a custom neck seam
For the head, we tried "Rope," which lets you draw a seam in stages. Drag on the visible surface, release, rotate the model, continue from the released endpoint, and close the loop by returning to the white starting anchor.
It felt precise, but drawing the seam takes practice. At first we relied on the view widget in the top right corner, and rotation was hard to control. Later we found that right-click dragging still rotates the view when "Rope" is selected, which made the process much smoother.
Once the seam was closed, we set "Follow Seam" as the cutting face and completed the head split.
The skeleton's geometry once again limited the connector options. The app reported that the cutting face was only about 2.6 mm wide, so the operation was completed without adding pins. It also flagged another disconnected part.
The lesson was straightforward: custom cuts work on fine geometry, but usable connectors need enough material around the pins and holes.
02 Testing auto-splitting with a snowman
Next, we loaded a solid snowman to test "Auto Multi-Plane," which calculates cuts based on the printer's build volume. We selected the Prusa XL preset. At its initial size, the snowman didn't need cutting—the app reported it would fit as a single piece.
A small scaling mistake actually provided a useful comparison. At about 500 × 500 × 1,101 mm, the app suggested splitting into 16 pieces. After setting the height to 500 mm and scaling width and depth to about 227 mm, only two pieces were needed.
The automatic planes didn't land on the natural joints between the snowballs. Auto Multi-Plane spaces cuts according to available print volume, so finding a good-looking seam still requires manual adjustment. The generated planes remain editable, and the app gives fit feedback when you reposition them.
This model also successfully accommodated built-in pins and matching holes. The initial 3 mm radius pins looked small on the enlarged snowman, so we undid the cut, increased the connector size, and cut again.
Adding a button and testing the sculpting feature
The tools on the right go beyond splitting. Using "Shapes," we added a sphere, resized it, placed it on the snowman, and merged it with one of the main body parts using a boolean union.
Boolean operations require exactly two objects to be selected. With both snowman halves and the sphere selected, "Union" was unavailable—a small workflow detail worth noting.
Sculpting was less successful. We tried the "Smooth" brush around the added button, and it noticeably softened the body bulge next to it, while the button itself barely changed.
The app warned that my small brush was finer than the model's triangles. Increasing the brush size didn't achieve the expected result either: the surrounding bulge was still affected. This test couldn't determine whether the issue was mesh resolution, brush positioning, or the beta itself, but precise smoothing was indeed difficult.
03 A promising cutting tool
The cutting features were the strongest part of this experiment. Plane selection, custom "Rope" seams, automatic splitting by printer size, and built-in connectors all provided useful control. Its warnings about loose parts and insufficient connector space were especially helpful. The interface takes some learning, especially distinguishing between "selecting objects to move" and "activating surface editing tools." Sculpting also needs more testing before we'd trust it for fine edits.
Still, for splitting models and preparing parts for assembly, this beta is already an appealing toolkit. The digital results were viewed on screen, and printability and connector fit still need to be verified with actual prints.
It's currently free, but it may not stay free forever. So go try it!
