During the boundary element integration of the Cool analysis, two elements were found to be in too close proximity to one another. If the distance between the centroids of two elements is less than 10 percent of the average edge length of either triangle, then the warning is triggered. This warning may arise if a cooling circuit element intersects a triangular element.
This warning usually occurs when two triangular elements of very bad aspect ratios are adjacent to each other. Another common cause is between two adjacent triangular elements of good aspect ratio that form a fold in the part and consequently have a very small included angle between the two elements. With Dual Domain meshes, this warning could arise when the part thickness is very thin and the opposing triangles are too large.