Technical functionality: selection of the measurement mesh
On EikoTwin DIC, the measurements are directly expressed on the simulation mesh. In order to choose which areas of interest for the test are visible to the camera(s), the so-called measurement mesh must first be selected.
Indeed, this mesh will be the one where the results will be calculated. It is, therefore, essential to select it correctly in order to obtain the desired results.
There are two modes of mesh selection: image selection and mesh selection. Depending on the type of geometry and images to be processed, both of these modes have their relevance.
Selection on mesh
This selection mode is useful when you know the area of interest on the mesh. You can these use 2 selection modes: selection by area and selection by angle. The selection by angle mode is particularly suitable for flat and cylindrical structures.
Thus, in few clicks, one can select all the elements whose normals possess angles smaller than a given value. The selection by area mode allows the selection of all elements within a rectangle that the user can adjust. Thus, one can easily select several areas of the mesh to make the measurement mesh.
Selection on image
In some practical cases, this selection mode proves to be particularly effective. Indeed, it allows the user to select directly on the datum images he imported, for each camera, the area of interest.
During the pre-calibration step, the software will then calculate the elements of the simulation visible visible by at least 2 cameras in the case of 3D calculations. This selection mode is suitable for complex geometries or when external elements are hiding part of the piece.
Use of EikoTwin DIC
Is it common practice to combine these 2 selection modes. For example, a first selection from image then refining from the mesh can be judicious. In the video below, we present these 2 selection modes in detail.