We have all seen surfaces that are too close together creating a flickering appearance in ARCHICAD and BIMx. The easiest solution is to move element incrementally farther apart until the flicker disappears. With coverings, moving the covering up and away from the roof can create a disassociation between the roof and the covering; meaning the covering will need to be rebuilt with any change in roof design.
There is a solution that keeps the covering associated and eliminates the flicker.
The roof shows an uneven appearance that changes depending on camera angle and movement.
Edit all roof coverings to have a minimum 1/4″ dimension at ‘Allow Space for Framing’
Flicker does not appear with 1/4″ spacing
It is also helpful to note that this setting is not required for all covering configurations. Corrugated metal, for example, does not have the same issue, since it has a natural depth that pulls most of the covering away from the roof. Standing seam or battens have large areas of flat planes that create the flicker, so they may require adjusting the framing thickness setting to get them to show as intended.
In the wake of our office presentation on Solid Element Operations, I have been getting a lot of feed back, questions, comments and suggestions on use of SEO’s and methods of modeling without them.
I want to point out three scenarios that I came across this morning. One is SEO’s done correctly, the other are wrong. These deal specifically with walls, columns and beams and their relationship to the roof elements above.
Columns extended beyond roof plane and trimmed with upward extrusion
The basic idea here is that elements are all extended beyond the roof and then cleaned up by using SEO’s. This is wrong for several reasons:
- First, this habit will cause more unnecessary SEO’s in the project. And we have already covered why that is problematic
- Second, these elements can interact, intersect, create voids in elements above, such as dormer walls
- Third, these walls do not clean up correctly with their roofs in section, wall section, details
- Fourth, it runs a risk of saving out incorrect or inaccurate IFC or SKP files
The correct method for making these walls/columns/beams flexible to design adjustments is to set them to the correct height relative to the story above. Top link the wall, even if it is grossly below the story above, as in this case where the floor to roof height is 18′ in the story settings; so the top of wall is -9′ to story above.
18′ floor to floor height for floor/roof stories
Wall Top linked to Roof and set at -9′
This has come up pretty frequently, in user group meetings, online forums, and here at WWA. I would try to re-explain it, but check out this link:
The graphisoft help center has done a great job of explaining a simple solution to this “complex” roof problem. One thing to note is the pitch break should be manually adjusted in the 3d window to avoid guess and check design.