case study

Robotic engraving on unknown objects

25 Apr, 2022

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Robotic engraving on unknown objects

Robotic engraving on unknown objects

This clever solution for robotic engraving on unknown, curved surfaces uses Photoneo 3D vision to get an accurate point cloud. The 3D data is then used for the creation of an optimal trajectory to navigate the robot with high precision.


Faculty of Electrical Engineering and Information Technology, the Slovak University of Technology in Bratislava

Department of Robotics and Cybernetics

National Centre of Robotics


European Structural and Investment Funds OP Integrated Infrastructure 2014 -2020


When engraving objects, the precision of the tool path is paramount as imprecise engraving can damage the objects. Usually, the engraving task is done on a known, flat surface by a CNC machine or laser. Therefore, our partners conducted a research project to investigate how to precisely create custom tool paths on an unknown curved surface.


PhoXi 3D Scanner L

The solution deploys a PhoXi 3D Scanner model L from Photoneo and the application was developed in Rhinoceros and Grasshopper.

The solution consists of the following steps:

  1. Scanning the workplace with the PhoXi 3D Scanner 
  2. Importing the captured point cloud to Rhinoceros
  3. Selecting the engraving area, setting where and what to engrave, and creating a toolpath trajectory. Paths are generated automatically from text or vector graphics.
  4. Measuring tool path deviations with a laser scanner. The optimized tool path has a standard deviation of 0,0313 mm.
  5. Engraving


The PhoXi 3D Scanner has been chosen for this application because of its high quality of point clouds, wide scanning range, ability to identify workpieces in the workplace accurately and precisely as well as its ease of use.

This solution is part of a research project but it can be further developed and used in other areas where it is necessary to approach each working object in a different way.