Revit can't generate custom truss

[arikadesu]

I've tried creating a stepped structural truss (where part of the top chord is independent)  from the "M_HOWE" out of the box family but after loading it into a project and trying to draw the truss in a plan view I receive the following errors:

"Revit is unable to generate a truss using the current Layout Family and Truss orientation."

"Truss is unable to generate any members due to layout family error."

This family flexes without error in the family editor and appears to function the way I want so I don't know why the truss isn't generated. 

Any ideas? I can upload the family if needed.

[sgonzalezNXU9D]

I am having the same issue

[MichaelDol]

1. It is always better to put a file out.
2. Dimensions must be referenced to reference planes.

[jose.pardalQASML]

Maybe did you create any group in the family? I experienced the same issue when importing truss families into the project. If for any reason you need to create a "group" (to develop an array, for instance), instead of "create the group", just select everything (including dimensions) that you want to group. Then, create an array. That will allow to "group" without create a group by yourself. Also, don't forget to delete any previous group that you created before. Go to the navigator browser and delete every group in the list. Hope this can solve your problem.

I learn this advice thanks to this video:

https://www.youtube.com/watch?v=COx51OcRXmA

[jose.pardalQASML]

Maybe did you create any group in the family? I experienced the same issue when importing truss families into the project. If for any reason you need to create a "group" (to develop an array, for instance), instead of "create the group", just select everything (including dimensions) that you want to group. Then, create an array. That will allow to "group" without create a group by yourself. Also, don't forget to delete any previous group that you created before. Go to the navigator browser and delete every group in the list. Hope this can solve your problem.

I learn this advice thanks to this video:

https://www.youtube.com/watch?v=COx51OcRXmA

[sgonzalezNXU9D]

Thank you very much @jose.pardalQASML  for your explanation and the video with the example. This was the solution to the problem I was having with the truss family I created.

The dimension between the bottom reference plane and the first and last element of the array makes my truss's web to change height correctly.