Mark,
I just tried my own suggestion and it only affects the 2D symbol
not the 3D model. I think that in order to get the 3D part centered
on the roof you have to calculate the width of the pans and covers
so they have a dimension that evenly divides into the width of the roof
and adjust the tile parameters accordingly.
John,
I have looked at the code for the roof surfacer and it uses
vertical cutplanes at the edges and if you change the code
so that the eave cutplane is perpendicular then if you have
a valley cut in the main roof for a cross gable there is a row
of cut tiles going across the valley cut at the eave line.
Not a problem for an unfinished attic, I often found pieces
of tile in attics, but if you have a cathedral ceiling,
there is that strange clay tile decoration hanging in space.
My work-around is to make a library part that makes a row
of wedge shaped starter tiles having a plumb upper edge with
a masking divice in the script to hide the lower edge of the
surfacer and a perpendicular lower edge.
Peter Devlin
P.S I wish Duane Valencia would pipe in.
He knows more than anyone about these issues.