When the  top molding line / base molding line is rendered black, first check whether the top/bottom line overlap caused the black, and then re-generate the top/bottom line.

Step 1: Open the solution, adjust the Angle of view to the front of the cabinet, click the top line/foot line respectively, when the left mouse button click the top line/foot line overlap, Delete the top line/foot line first;

Step 2: Check whether there is overlap in the cabinet and re-place the cabinet;

Step 3: right-click the wall, select all lines - install the top line/foot line;

Step 4: Select the style and material, modify the section height.

Finish: