Free 299 Tools Blender add-on slices AI figures into parts for 3D printing

The author of 299 MODEL WORKS, a Japanese website about scale modeling, has released 299 Tools for free — a set of seven tools for Blender. The set grew out of recurring tasks the author faced when turning AI-generated figures into parts for 3D printing. The add-on splits a model into parts automatically, cuts it along a drawn contour and leaves a clearance between parts so that they fit into each other after printing. The set may be used in commercial projects, and models and figures made with it can be sold.

Version 1.0.0 was released on September 9, and the official page already lists version 1.0.1.

Tools born in the author's own workshop

On the 299 MODEL WORKS site, the author publishes builds of motorcycles, cars, aircraft, armored vehicles and figures. Two days before the release, the project blog published a report on printing an original figure whose model was made in Tripo. It describes the difficulties: thin areas had to be reinforced with putty, and the face did not fit into the hair part. According to the author, checking assembly and part intersections is harder in Blender than in CAD. The set includes solutions to problems that came up again and again when preparing AI meshes for printing.

The centerpiece: automatic splitting into parts

The core tool of the set is Auto Segment. It analyzes a solid mesh and suggests candidate parts based on changes in thickness, concavities and folds. The result is color-coded. Unsuccessful pieces can be split again or merged with neighboring ones, and only then are the boundaries locked in.

The developer tuned and tested the set mainly on figures created by neural networks. Auto Segment is not designed for hard-surface models, that is, vehicles and other objects with rigid shapes, and the author explicitly warns that it will most likely split such objects poorly.

Cutting, capping cuts and fitting joints

The remaining tools cover the steps that follow segmentation. Freehand Cut lets you draw a closed contour directly in the viewport and project it onto the mesh. Before deleting, the tool shows the affected faces, so a bad selection is visible in advance. Straight-line cuts are also possible.

Surface Bridge builds a curved surface between two edge chains along an open boundary, and its shape can be adjusted with control points before confirming. This is how open areas of the mesh get closed. The author sees this surface as a base for further sculpting.

Clearance Boolean handles how parts fit together. The tool expands the cutter object and performs a Boolean difference, leaving a specified clearance between the parts. The author warns that on complex meshes the operation can be slow and in some cases fails altogether.

Three more tools are auxiliary:

• Size from Head Proportion calculates the final head size and scale factor from the current head size, the character's intended height, body proportions and the target model scale.
• Simple Pose Helper creates a simple rotation axis for the selected area. It is meant for minor pose adjustments when setting up a full armature isn't worth it.
• Backface Check uses Blender's built-in Face Orientation display mode to quickly reveal flipped faces by highlighting them in red.

Limitations and distribution terms

The add-on was developed and tested in Blender 5.0 on macOS, on a Mac mini M2 with 16 GB of memory. The set has not been tested on real hardware under Windows or Linux: according to the author, a Mac is the only machine available. The author also warns that this is the first public release and that other data may reveal issues that did not show up during testing.

The license permits personal and commercial use with no restrictions on selling models, 3D data and images made with the add-on. It is prohibited to distribute, re-upload or sell 299 Tools itself or modified versions of it, or to include it in other bundles. Officially, the set is distributed only through 299 MODEL WORKS: 299 Tools is downloaded as a ZIP archive from the author's page. The page also hosts manuals in English and Japanese and a bug report form.

Why tools like this are appearing now

AI 3D model generators have made figure characters accessible to people without sculpting skills, and some services already offer mesh preparation for printing. The output, however, is usually still a single solid model. To print a figure as a multi-part kit that is easy to paint piece by piece and fits on the printer's build plate, it has to be cut, the cuts capped and the joints fitted. This stage still remains largely manual.

Existing tools cover it only partially. Blender's 3D Print Toolbox extension focuses on mesh diagnostics and repair, Autodesk no longer develops Meshmixer, and slicers such as CHITUBOX cut the model with a plane and add connectors but do not take the character's shape into account. The emergence of add-ons like this probably indicates that the community's interest is shifting from generating models to finishing them into physical objects.

The release will likely be most useful to hobbyists and small garage kit workshops: they get a free set with permission for commercial use. There are limitations too: the project appears to be run by a single author, and testing was done only on Mac, so support for future Blender versions depends on that one person. If the trend continues, automatic splitting and clearance calculation will probably become built-in features of generators and slicers over time, leaving 3D modelers to check joints and refine parts.

Which of the 299 Tools would you use most often?

• Automatic splitting into parts
• Contour cutting