Steps:
1) CADFEKO: When having ERROR 240: A triangle is smaller than the model tolerance in RCS_error240.cfx, check which triangle is erroneous from the RCS_error240.out file.
2) POSTFEKO: Locate the faulty triangle (#1) with Mesh tab > Find elements.
3) CADFEKO: Check where the faulty triangle is and which faces are surrounding the triangle.
4) CADFEKO: Select the original geometry, apply “unlink mesh … “, and delete or exclude the original geometry.
5) CADFEKO: Apply “Use model mesh” to the new unlinked mesh.
6) CADFEKO: In the detail tree, select the face (having the faulty triangle) and the surrounding faces, apply “merge meshed” for the selected faces with a right mouse key and give a new name to the merged face.
7) CADFEKO: Mesh again and run FekoSolver.
