Why did I develop Crobics, a free online 3D modeling tool for DIYers and Makers?

3D modeling is an essential app to take advantage of a 3D printer. As soon as you start having interest for 3D printing, you quickly realize that before you can print an object, it is necessary to model it, and that it is difficult finding an affordable application fitting your needs, mainly if you want just design a simple object, let’s say a plastic part to repair a chair or a furniture or even a box for an electronic board you have just built but not an entire car engine.

When I bought my first 3D printer, 4 years ago, I quickly realized that I had nothing for designing the objects. The professional CAD tools were too expensive, long to learn. Other free available tools were not satisfying my needs and some of them were producing models with errors, leading to bad 3D printings.
I wanted a tool looking like my workbench, and with which I could work like on my workbench with my preferred tools: saw, drilling machine and glue. The resulting object should be without errors in the mesh.

At this time, I decided to develop my own 3D modeling application,.

The result is Crobics, a free online application designed from the beginning to draw 3D models easily with concepts and tools understandable by everyone, provided that you have already stand up in front of a workbench, handling a saw a drill machine or glue.

Crobics is based on very simple principles:

  • It is free and you don’t need any registration for using it.
  • It runs online in your browser, meaning that you have nothing to install if you want to try it. Your files are saved on your computer as a file download, either in Crobics native format or in STL format for your 3D printer.
  • It runs with or without (default) Webgl by selecting an option. You can run the application even with an old graphics board and even with an old computer.
  • You can build a solid from primitive shapes, from a curve delimiting the base of the solid or by lathing a curve for solid of revolution. Threaded shafts are included in primitive solids.
  • You can glue solids together, drill a solid with several shapes or saw a solid. You can drill a threaded hole.
  • You can build your own tool for material removal
  • You can of course move a solid on freehand basis or step by step or rotate a solid.
  • You can work with one single view or 4 views to have in a glance the view of the result from various angles.
  • It is advice working as much as possible in “2D” (front, left, top,…) and rotating the view in “3D” mode only for result verification. Some tools will only work in “2d” mode.

The purpose of CROBICS is to open 3D modeling to everyone and to convince everyone that he/she is able to create a 3D model, at least for simple objects.
Even children are able using this software. During workshops, children from 9 years old were able using it to design their own model.

The main advantage of the app is its ease of use, but it does not mean that you should not explore the manual before starting. It is necessary to understand the different commands and how they can be used, but when you have understood how it works, you will not forget it, even if you use the app rarely.
The e. It checks at every step of the modeling that the result is a correct solid.

CROBICS runs a site,, where individuals or small businesses that do not have CAD skills can access a free online 3D modeling software. Users can then retrieve the model in STL format for use as they wish. The site and the application are available in English and French.

Although it is simple to use, it includes features like the design of threaded shafts, drill with threads (tap), building of a solid from a curve or lathing of a curve to build a solid.

The software can load STL files to modify it. Currently the files must be free of errors, but this restriction could be removed in the future.

Manuals are available to start using the software and to go deeper with some features.