Continuing in the spirit of Ryan's "Tips" sections, I thought I'd offer some tips for beam cutbacks. The way a beam cuts back in a connection is different in Coarse/Symbolic versus Medium/Fine. This post will deal with cutbacks in Coarse/Symbolic Detail, and I'll cover Medium/Fine in a second post.
If your beams aren't cutting back correctly in Coarse representation, there are a few things to check:
1. Is the issue isolated to a few beams or is the cutback incorrect throughout the file?
If none of the members are cutting back correctly, check the Structural Settings dialog in the Symbolic Representation Settings.
2. Have you added start or end extensions?
If so, extensions do not display in Coarse detail, so they would need to be added with linework.
3. Are there differing elevations in the connection?
Depending on the elevation difference, the cutbacks might not calculate. You can avoid this by using the Z-Direction Justification parameter in the beam's Instance Properties. For example, you might want a joist seat to sit on top of a framing member. Rather than adjusting the Start and End Level Offsets to accommodate the height change, set those to 0' 0", set the Z-Direction Justification parameter to Other, and set the Z-Direction Offset value to the height above (ie 0' 2 1/2").
4. Are you using a custom symbolic representation?
Check the beam family settings to see how the representation is defined. Edit the family and go to the Create ribbon and select Category and Parameters. In this dialog there is a Symbolic Representation family parameter than can be set as From Project Settings or From Family. This determines whether the symbolic representation is defined by the family or the settings of the project in which it is placed.
5. Is your beam framing into a column?
If so, check the cutback settings associated with the column family. Edit the column family and enter into the Category and Parameters dialog. There is a Beam Cutback in Plan parameter that can be set at From Bounding Box or From Geometry. This will determine whether the beam cutback is determined from the column bounding box or the physical geometry of the column. Something like this might come into play if the column has nested components such as a foundation or plate together in the family.
6. Is your beam a custom family?
If so, try replacing the beam with an out-of-the-box family to see if the issue is due to the way a custom family was created.
7. Does your connection need regeneration?
If the steps above don't resolve the issue, try cutting and pasting the members to see if the representation appears correctly. If necessary, recreate the members associated with the connection.
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Very helpful series! could you add 8, 9 or 10 explaining how to force a joist to frame to a beam which is inline with a wall instead of trying to turn the wall into a bearing wall?
Posted by: Andre | August 21, 2009 at 11:00 AM