Hi!
Copy one of your triangles and snap the vertices to the surrounding vertices. Do not flip the triangle, all triangles need to have same orientation (clockwise or counter clockwise)
Last thing to do is to save the triangles, you can use "Edit/View Surface", save triangles or Import triangles. To check if the surface has any holes, use the "View perimeter" command. Holes would have perimeters.
The difference between saving and importing
When you plot CadTools triangles into a DWG the triangles X-data are marked as "CadTools triangles", when you use the save triangles command in CadTools only objects with the correct X-Data is saved. The import triangle command saves the triangles (3D polylines or 3Dfaces) without checking X-Data
