Getting Started

WORKZONE TREE : HOW IT WORKS

The Workzone is the main working area where all intermediate and resulting files are created and managed.

When you use Prepare or Presplit functions:

Repaired parts
Oriented parts
Scaled parts
...

are automatically added to the Workzone.

The Workzone allows you to:

Visualize all generated elements related to the current project
Select which file or plane is active
Keep track of the different steps of the preparation process
Files created in the Workzone are linked to the original model and reflect the operations performed on it.
The Workzone acts as a staging area before exporting or further processing the parts.
...

.s3r project file = Workzone settings.

The .s3r file stores Workzone parameters: selected printer, plane positions, UI options, and other session data for this project.

The tree is now color-coded so you can read it at a glance (<model> = your file's name):

Green : the active part, e.g. <model>.ply
Orange : Split results → splits_<model>/
Blue : Extract results → extract_<model>/
Violet : Cut by Plane results → cut_<model>/
Yellow : Sort-by-color results → colors_<model>/

Technical and backup folders (those starting with an underscore, like _backup_<model>/ and _export_3mf/) are hidden by default so you only see your useful parts.

Right-click anywhere in the tree → "Show Hidden-Backup folders" to reveal or hide them.
Then you can "Restore as current body" to restart and continue

(Older projects keep working, their results sit in results_<model>/, shown in orange.)

VISIBILITY LOGIC.

Checked → The part/file is visible in shaded mode in the 3D view.

Each file includes a dedicated visibility icon (next to the checkbox).
This icon allows you to display parts in a semi-transparent overlay mode, making it easier to understand how pieces fit together before finalizing your cuts.

You can now act on a whole results folder at once: tick a folder's checkbox (e.g. splits_<model>/, extract_<model>/) to show all its parts in one click, or use its ghost icon to make them all semi-transparent together.

ACTIVE FILE
The Active File is the file currently used by all functions in the Prepare workspace and by the Presplit process.
The Active File is always kept at the top of the Workzone under a stable name.
Only one file can be active at a time. The Active File is displayed in Green Bold in the Workzone tree.
All operations such as Analyse, Repair, Orientation, Autoshell,... and splitting are applied to the Active File.

Before using any Prepare or Presplit function, make sure the correct file is set as active.

Activate STL: Double clic on it in the tree or Right-click and choose Activate to make it the Active file
Only one file can be Active at a time.

DELETE

Delete: Right-click and choose Delete to remove unneeded files/folders results from the Workzone or hit "Del" key.
Note : You can now delete the active part too: Split3r removes it from the 3D view and automatically loads the nearest remaining file in the same folder. Only deleting a folder that contains the active part is still blocked, switch to another part first.

IMPORTING A COLORED 3MF (BambuStudio / PrusaSlicer)

Open a 3MF with multiple bodies, multiple plates via File > Open or drag and drop.
Painted colors are imported from BambuStudio or PrusaSlicer. (Each slicer uses its own on-screen palette, so colors follow what's stored in the file.)
Multi-plate files: a dialog lets you pick the plate to import, with a thumbnail.
A progress bar shows the conversion

The model lands as a colored part (.ply) and keeps its colors through repair, split, extract and cut.

ANALYSE

The Reality of 3D Files

After analysing support tickets from over 2,500 users during the first six weeks of Split3r's beta release, we identified a consistent trend: over 80% of reported issues stemmed from problems inherent in the files themselves, rather than software or user error.

We all download models from popular repositories like Thingiverse, Cults3D, Printables, or Thangs... While these platforms are great resources, many uploaded files are modeled for visual purposes rather than manufacturing.

Consequently, they often carry severe geometric defects that make them unsuitable for operations like cutting or splitting.

To help you identify these "dead-end" files before you waste time trying to split them, we are introducing a raw Analyze command. It doesn't modify your file, it simply exposes the truth about its geometry.

What it detects:

The tool scans for specific defects that cause boolean operations to fail:

Multi-Body STLs: The Blender mathematical engine we utilize cannot perform cuts on files containing multiple disconnected bodies.
Non-Watertight Meshes: Open edges and holes.
Self-Intersections: Geometry folding into itself (often invisible from the outside).
Multi-Body Collisions: Internal overlapping volumes that confuse slicers.
Non-Manifold Geometry: Mathematically impossible shapes.
Foldover Faces: mesh faces that are folded onto itself, like a sheet of paper bent into a “Z” shape.

Simply click on the icon, it analyses the Active file (the file displayed in Bold in the Workzone).

Before processing, Split3r pre-analyzes your STL file structure and presents options
File structure report: Shows the number of bodies detected in your file

When multiple bodies are detected, choose:

Analyze as-is : Process the file without modifications
Keep largest body only : Automatically discard smaller elements (often usefull for AI generated files)
Keep top N bodies : Retain only the N largest bodies (generally for CAD generated files)
Keep all bodies : Preserve everything and create separate entries in the WorkZone (Explode everything in independant files)

Multi-body Multi-color models: "Keep all bodies & sort by color"

When you analyse a model made of several separate bodies (very common with multi-color 3MF files), Split3r asks how you want to handle them. On a colored model, one of the choices is "Keep all bodies & sort by color."

What it does:

It keeps every body, nothing is merged, and small bodies aren't discarded.

Each body is saved as its own part and filed by its dominant color.

The parts land in colors_<model>/, with one sub-folder per color, named by the color's RGB value.

For example a red part goes to colors_<model>/255_0_0/, an orange one to colors_<model>/255_128_0/, and so on.

Bodies that have no color go to colors_<model>/uncolored/.

Why it's handy: before printing a multi-color model, you instantly see which parts share the same filament color, all the reds in one folder, all the blues in another, which makes sorting parts, assigning filaments and organizing your prints much easier.

When the export finishes, Split3r switches straight to Explode so you can review all the sorted parts (and the yellow tint in the tree marks them as color-sorted results).
The Files are ready to export in 3mf and print (one click : Files > Export Workzone to colored 3mf )

REPAIR (Stable but subject to evolution)

The Repair function has been fully redesigned and now provides three distinct repair options, allowing users to choose the most appropriate strategy depending on the geometry and origin of the file.

1. Repair using standard algorithms
This option first merges internal bodies (when technically possible), then repairs common mesh issues such as self-intersections, inverted faces, holes, and duplicated or overlapping faces.
This method successfully repairs the majority of CAD generated files.

2. Repair using Split3r algorithms (organic part, AI parts and 3DScan parts)
Optimized for organic shapes and AI-generated models. This enhanced algorithm (deep repair) successfully repairs many files that other tools can't handle, making it particularly effective for AI-generated content and sculptural models.

Note: May not be optimal for mechanical/CAD files.
It is particularly effective on organic or scanned parts, but may deform some mechanical parts.

3. Repair using Blender algorithms
This option is intended as a last alternative when previous repair methods do not produce satisfactory results.
Repairs can be executed in sequence (for example, 1 followed by 2).

Repaired files are clearly identified:
Files repaired with method 1 are named R1
Files repaired with method 2 are named R2
Files repaired with method 3 are named R3

If multiple repairs are applied, file names reflect the sequence (e.g. R1-R2)

SIMPLIFY (New in version 1.4.0 - beta)

The Simplify command reduces the triangle count of a heavy STL while preserving its overall shape.
Useful on dense scans or high-poly models that slow down the slicer or Split3r itself.

Input: Active file (e.g., Demo-Rep.stl).
Output: Demo-Rep-Sim.stl added to the Workzone.

Use cases: Lighten scanned or sculpted models, speed up slicing, reduce memory usage before AutoShell or Cut by Plane.

Open the Simplify dialog on the active file. A slider lets you choose the reduction rate, from 24% to 99%.
24%: light cleanup, geometry almost unchanged.
50–70%: good balance between size and visual fidelity for most models.
90%+: aggressive reduction, use for rough previews or very dense meshes.
Move the slider to the desired value and click OK. The simplified file is added to the Workzone with the suffix _Sim.
TIPS & NOTES
Start around 50% and decrease only if the result is still too heavy.
Simplify is non-destructive: the original file remains in the Workzone, the simplified version is a new entry.

ROTATE

The Rotate command allows you to rotate/orient your part before further operations.

Rotating the part
Rotate the model by clicking on the colored arcs:
Red: rotation around the X axis
Orange: rotation around the Y axis
Green: rotation around the Z axis

By default, the rotation is applied in 5° steps.
Hold CTRL to switch to 1° rotation steps for fine adjustments.
Hold SHIFT for free (continuous) rotation.

Validating the orientation

Click OK to confirm the orientation.
The rotated part is saved in the Workzone with the suffix _O (for oriented) added to its name.

SCALE

Scales the active model before splitting (useful to match target size or compensate for shrink).

Input: Active file (e.g., Demo-Rep.stl).
Output: Demo-Rep-Sca.stl added to the Workzone.
Modes: Percentage (%), Absolute dimension (X/Y/Z ) or Factor : eg :1.5 .
Safety: Non-destructive; creates a new step in the pipeline.
Project behavior: The current Pre-Split setup is automatically disabled before scaling, you’ll c-onfirm the change if the scale factor is very large (> 20×).
Tip: Verify the new scaled file is Active before proceeding.

HOW IT WORKS

Input format: Enter a value with factor, unit or %, so the app can compute correctly.
Percentage: 150%
Millimeters: 855mm IMPORTANT do not forget to add mm after the value 855mm not 855
Factor (unitless): 1000 for example with a STL file stored in meters unit (leave unit empty)

Per-axis inputs (X, Y, Z): You can fill 1, 2, or 3 fields.

One value only: The other axes are computed automatically to keep proportions (no deformation). (Most common case.)

Two values: The specified axes are scaled independently; the unspecified axis does not change.
Example: X=120%, Y=130%, Z= (empty) → deform X and Y, keep Z unchanged.

Three values: The part is scaled/deformed independently on each axis using the three inputs.

Mixing units is allowed:
Example: X=120%, Y=568mm, Z=1.6 (factor)

TIPS & NOTES:

Use percent for relative growth/shrink, mm for targeting a precise dimension, or factor for quick ratios.
Very large factors (> 20×) trigger a confirmation.
After scaling, a new file (e.g., *-Sca.stl) is added to the Workzone, make sure it is Active before PRE-SPLIT.

SMARTSELECTION / EXTRACT (New in version 1.4.0 - beta)

The SmartSelection / Extract command lets you isolate a region of the model with a single click and extract it as a separate printable part.

Input: Active file (e.g., Demo-Rep-Sca.stl).
Output: Two new files added to the Workzone: the extracted region and the remaining body, both closed and watertight.
Use cases: Remove a feature for separate printing, split a model into logical sub-parts, isolate a damaged zone for repair, prepare multi-material or multi-color prints.

HOW IT WORKS

Click a face on the model. Split3r analyzes the surrounding geometry and automatically selects the region that makes sense to extract.

Refine the selection if needed:
Add zones: click on adjacent faces to extend the selection.
Subtract zones: remove faces you don't want to include.
Fill holes: close small gaps inside the selection.
Clean edges: smooth the selection border for a cleaner cut.
When the selection is ready, choose how to close the cut.
With Interlockig option, a live preview is displayed before extraction.

CLOSURE OPTIONS

Interlocking: a keyed joint that allows clean reassembly of the two parts after printing. Both the joint size and the draft angle are adjustable, so you can tune the fit between the parts and make assembly easier.
Patch: a flat closure across the cut. Fast and simple. Ideal when the two parts don't need to be reassembled, or when the contact surface is mostly flat.

Click OK to run the extraction.
Extracted parts go to extract_<model>/ (blue, named Extract_001, Extract_002…); the part you keep stays loaded under a stable name; the original and in-between versions are kept in _backup_<model>/ (hidden), so an extract is reversible.

Extend the smart selection.

Shrink the smart selection

Clear the current selection

Paint Triangle: add or remove individual triangles from the selection, hold CTRL and drag to add faces continuously, ALT and drag to erase.

Paint Sphere: add or remove every triangle contained inside a sphere. Useful for fast broad edits.

Fill: closes all holes and channels inside the selection.

Clean: removes sharp triangle spikes along the selection border for a cleaner cut

File “Bowser” courtesy of EON3D

TIPS & NOTES

CTRL+Z / CTRL+Y (Undo /Redo) are avaliable during preparation.
Click on the convex part for the first selection; this usually works best
Use Patch for permanent separations and Interlocking when the final object must be reassembled
Use Fill and Clean command before Extract Command
With interlocking mode Check the preview before extraction, the closure geometry is visible and can be adjusted without restarting the selection.

AUTOSHELL

Creates a printable shell (hollowing) on the active model with a specified wall thickness.

Input: Active file (e.g., Demo-Rep-Sca.stl).
Output: Demo-Rep-Sca-She.stl added to the Workzone.
Use cases: Reduce material, speed up print, enable lightweight parts while keeping exterior shape.

THICKNESS GUIDELINE

Note on limitations: Depending on the shell thickness you choose, the numbering of parts may no longer be possible if the shell is too weak.

Recommendation: Avoid creating shells thinner than 15 mm to preserve enough space for tenons and tolerances.

Why: Thicker shells provide reliable tenon seating, reduce breakthrough risk, and improve bonding area.

Tip: If your tenon template is large or includes fillets/chamfers, consider ≥18–20 mm shell thickness. Adjust tenon spacing and offsets accordingly before running Split.

Of course, avoid trying to create an autoshell on small parts that are smaller than the thickness of the shell!

VOXELS AND MODEL SIZE

AutoShell uses a voxel-based representation of the model for the internal shell.
A voxel can be seen as a 3D pixel: a small cube used to describe the volume of a part.

The voxel size defines the size of these cubes and therefore the size of the internal facets generated by the software.
Small voxels = high precision, many internal facets, high memory usage
Large voxels = lower precision, fewer facets, better performance

The number of voxels increases very quickly with the size of the model.
For example, a part measuring 3000 × 2000 × 1000 mm with a voxel size of 3 mm generates more than 220 million voxels, which can easily exhaust your PC’s memory.

Recommendations
The voxel size must be adapted to the overall size of the part and the power of your PC:
Parts larger than 1 meter: approximately 5–7 mm
Parts around 2 meters: approximately 10–15 mm
Using a voxel size that is too small for large parts may lead to severe slowdowns or crashes.
Always start with a larger voxel size and reduce it only if higher precision is required.

Note : This function is expected to evolve in future versions, with the introduction of an automatic voxel size adjustment based on the part dimensions, in order to improve usability and reduce the risk of excessive memory usage.

CUT BY PLANE

The Cut by Plane command allows you to cut the active part using the currently active cutting plane.

A dedicated 3D gizmo lets you freely position and orient the cutting plane in any direction, giving you full control over the cut location and angle.

Standard Angle and Move step are fixed to 5° - 5 mm
Shift Key disable angle and move Step.
CTRL Key set Angle and Move step to 1° - 1 mm

Once the plane is positioned, you have two cutting options:

Cut All : Cuts the entire part using the active plane.
Cut Selected : Cuts only the selected portion of the model.

This selective cutting option helps prevent unwanted areas from being split.

When the command is executed, the system:

Cuts the model according to the active plane
Automatically adds the preselected connectors (tenons) to the cut surfaces

Connector options are available, including the possibility to add only a single tenon if required.

Cut-off pieces go to cut_<model>/ (violet, named Cut_001, Cut_002…); the part you keep stays loaded under a stable name; previous versions are kept in _backup_<model>/ (hidden), same reversible logic as Extract.

⚠️ Recommendation:

We strongly performing plane cuts before using the AutoShell function.

This approach allows you to create shells directly in the individual parts generated by Cut by Plane. In addition, the tenon geometry is automatically integrated into the AutoShell process, ensuring proper internal thickness and cleaner results.

What you did	Folder	Color
The part you're working on	<model>.ply (top of Workzone)	Green
Split	splits_<model>/	Orange
Extract	extract_<model>/	Blue
Cut by Plane	cut_<model>/	Violet
Sort by color	colors_<model>/	Yellow
Automatic backups	_backup_<model>/	hidden
3MF export	_export_3mf/	hidden

Split3r GETTING STARTED

INSTALLATION

SOFTWARE ACTIVATION

QUICK TEST

DARK/LIGHT DISPLAY

4 x MODES

PREPARE

PRE-SPLIT

SPLIT

EXPLODE

PREPARE MODE

WORKZONE TREE : HOW IT WORKS

VISIBILITY LOGIC.

DELETE

HOW IT WORKS

TIPS & NOTES:

HOW IT WORKS

CLOSURE OPTIONS

TIPS & NOTES

THICKNESS GUIDELINE

VOXELS AND MODEL SIZE

PRE-SPLIT MODE

PURPOSE

1) PRINTER SELECTION

2) CUT SIZES

3) MOVE STEP

4) MOUSE-DRIVEN PLANE ADJUSTMENT

5) TENON TYPE & TEMPLATE

6) CONTROLS & HOTKEYS

7) TYPICAL WORKFLOW

NOTES & BEST PRACTICES

SPLIT PARTS

PERFORMANCE & PARALLELISM

EXPLODE MODE

TREE MANAGEMENT

MULTI-SELECTION & CONTEXT MENU

Multi-selection in the tree

Visibility rule with selection:

Right-click on a tree label

Menu actions (as shown bellow):

BUTTONS & SHORTCUTS

FILE STORAGE

Multiple splits per WorkZone

Connector files (tenons) for assembly