Shadow and fill weirdness

[Anonymous]

(This is copied from an enquiry I sent to Cadimage recently, they don't appear to have an answer. Appologies for its longwindedness-ity)

I am having trouble with some Elevations which are doing funny things with shadows, fills and windows.

I have some items on 3D only layers, which when turned on for the Elevations seem to give me strange results. Elevations are set to "Fill uncut surfaces with: elements own material", vectorial fills on and shadows on. I have used roof accessories to show gutters, downpipes, shingle roof (set to flat surface with material/vectorial fill). The accessories have produced their own problems, like shadow under gutter making the fascia transparent in some locations, but minor adjustments have resolved this. These are on Slab-Roof layer which is ON in Floor Plan layer combo. 3D model layers contain gable end walls, Quoins at corners (Coyne 10 object from Basic Library / Building Structures / Wall Extras library), and additional wall elements to add contrasting stone banding at various levels. Initially I had no problems with these elevations, but now I am getting unexpected shadows as shown on the attached image. The windows that are filled / hatched have been fine until just now while exploring these other problems, but have now gone weird and I can't find a reason why.

I have tried moving Elevation lines to regenerate the problem elevations.

I have restarted Archicad, to no effect.

(A point which has some effect: the windows (DWBuilder) have an exterior trim 20mm thick x 100mm wide, when this is turned off shadow strangeness disappears. Also, when Floor Plan layer combo is on (i.e. 3D model layers OFF) but accessories and window trim still ON, shadow strangeness disappears.)

Any suggestions as to why this is happening, and possible fixes would be greatly appreciated.

Thanks for your time.

[Anonymous]

Here's the same elevation with 3D model layers OFF