You may encounter this error when creating sloped glazing or a curtain element where the layout cannot support a small panel or mullion.
Error: Can't create curtain panel. A panel or a mullion is probably too small.
Issue: A horizontal and vertical curtain grid on a panel are not meeting exactly at a point, creating a small triangular panel within the main panel. The triangular panel cannot be accurately regenerated, because it is too small. This error can result from placing curtain grids, or moving one in such a way that the small triangular panel displays. Also, the triangle can display, if you created vertical grids and then placed a horizontal grid that did not snap to the vertical grids.
Solution: Cancel the placement and/or the movement of the grid. When dividing the panels in a sloped glazing, it is best to start with the placement of horizontal curtain grids and then snap vertical grids to the horizontal grid.