Category Archives: Roof

Smarter Modeling & Top Link Settings

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.

Screen Shot 2016-04-28 at 9.39.51 AM.png

Wall perpendicular to roof slope trimmed to roofs with upward extrusion

Screen Shot 2016-04-28 at 9.40.13 AM.png

Wall parallel to roof slope, extended to ridge height and trimmed with upward extrusion

Screen Shot 2016-04-28 at 9.40.04 AM.png

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.

Screen Shot 2016-04-28 at 11.12.55 AM.png

18′ floor to floor height for floor/roof stories

Screen Shot 2016-04-28 at 11.12.47 AM.png

Wall Top linked to Roof and set at -9′

Gable End + Hip + Multiplane Roof

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:

helpcenter.graphisoft.com

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.