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Modelling and drafting in ARCHICAD. (Example: How can I model a Roof soffit/fascia?)

Moderators: Karl Ottenstein, LaszloNagy, ejrolon, Barry Kelly, gkmethy

Hi all

Has anyone experienced this issue before? In 3D mode, the outlines of walls are showing through the roof when you are zoomed far away. The roof and walls are trimmed via the Trim operation. When you zoom in closer the outline of the walls disappear.

It looks fine in 2D roof plan view.

Any resolution would be appreciated.

walls & roof (Medium).jpg
It it not just you benjamin_chan,
it's a long standing problem with ArchiCAD that never gets fixed. Apparently GS does not think it is very important. Either that, or it is a really difficult problem to fix. ??
I see most of my rafters through my roofs from a distance in the 3d window. Not really an issue I find though as it renders correctly. One aspect it might impact though is the refresh of the 3d window might a bit slower... a lot more contours that don't actually need to be calculated...

In this specific case it looks like you could be using the Roof Accessory tool for Roof Surfacing. ( could be a texture too - not sure) If you give Geometry box 3 a dimension of say 1/16" or so it may solve your problem. It works for me. As you can see in this picture one roof has no space between the roof sheathing and the metal roof surface object, and the selected one does.

Does this just show in the 3D window? Are renders and 3D documents ok? If so, this is just a function of the ‘live” display. Many 3D programs do this to speed up refresh - it’s not a bug or a fault.
Hello everyone,

Yes, it is very common, but it is not a bug, it's just how OpenGL works. Since those edges and the outside surface of the roof are very close to each other, after a certain distance, it just overlaps. You should also see similar things through thicker elements as well from greater distance.
If you use very thin layers of coating on something, that can also give you a "flashing surface effect". These are just a limitations of our OpenGL technology, since the focus of the OpenGL was never to make renders/visuals, but creating a relatively fast 3D workspace.

Since this is just a display issue that's only present in OpenGL, renders in Cinerender and the Vectorial Engine should not be affected.