Shared Parameter Reference Plane Issue

[bm]

Hi everyone,

I'm trying to create a tool to visually highlight certain portions of a beam.  To acheive this, I created a simple parametric "cube" in the W Flange beam family where the size and position (with respect to the beam) of the cube are all controlled with shared parameters.  

All of the parameters work great when testing them within the family, but when loaded into the project, the parameter that is supposed to move the cube up and down relative to the bottom of the beam (parameter is called 'From Bottom')  is shifting the beam's position instead of the cube's. 

I've seen a similar issue on another post, but still haven't been able to figure this out.  What is confusing to me is that a similar parameter ('From Edge'), which controls the position of the cube relative to the beam's edge works fine (it doesn't move the beam's position left and right).

Any and all advice and help is greatly appreciated.  Attached is the W Flange with Cube family file, along with a sample project as illustrated below.

Thank you in advance for your help.

-Brendan 

 

[Alfredo_Medina · Accepted solution]

This has nothing to do with your parameters being shared or not shared. The issue here is that you are actually affecting the extents of the beam family in the up and down direction everytime the cube moves to a position in which a face of the cube is higher or lower than the steel. Revit uses the extents of the family to determine the z-justification. Therefore, in the project, if you move the cube up, and the "z Justification" parameter is set to Top, Revit keeps the family (the cube and the steel) so that the family keeps being justified to the top.

The left and right movement of the cube works because in this case the cube does not interfere with the z-justification parameter.

I don't see a decent solution to this issue. Manipulating other parameters in the beam's properties just to get this cube at the right position is not a good idea because that could eventually create a mess with the structure. Not recommended.

[conormccartney3897]

Exactly as Alfredo said. However, you can add a visibility parameter to the cube, when your done using it for that particular beam, turn it off, and it will be ignored, we do this with fireproofing all the time.

[bm]

Thank you both for your words; your insight helps out a lot.  The vertical extents of the family explains a lot about this behavior and why this issue is happening. 

The main reason for creating the cube in the beam family and using shared parameters is in hopes of obtaing the geometric cube information along with specific beam properties in one schedule.  

I'm hoping to find a way to constrain the cube to the beam's dimensions/parameters such that the cube would never impose on the extents of the beam.  For instance, limiting the 'allowed' cube distance from the bottom of the beam to being less than that of the depth of the beam (then having a similar constraint for the depth of the cube in relation to the depth of the beam).  Is this possible using formulas & beam parameters? 

Once again, any thoughts, ideas, or suggestions is much appreciated.      

[Alfredo_Medina]

What is the meaning of the different locations of the cube? Maybe this can be made in a different way.

[bm]

Hi Alfredo,

The cube is to represent a volume of a certain type of damage on a particular beam.  In the model, the cube will serves two purposes:  to visually illustrate where a beam is damaged, and to use the cube size/position information along with the beam's structural properties to perform some structural analysis using a different program.

In the case of the cube/W Flange family, the cube could represent the volumetric section loss due to corrosion of the beam.  The location/position of the cube is important because it will have a great effect on the capacity of the beam when the structural analysis is performed.  

My model is currently set up with the beams and cubes in separate families to avoid the aforementioned vertical extent issue.  This all works great in the model but I need the beam properties & cube size/position info all on one schedule to use as kindof an "input" file for my structural analysis.

Thank you for your continued posts.  I'm pretty new to Revit and your posts and forums such as this are my primary resource for learning this awesome program.

Do you have any suggestions as far as somehow constraining the cube dimensions to not affect the vertical extent issue?  Or any other ideas? 

[Alfredo_Medina]

I assume that the size of the cube is not important, but its location. Therefore, the size of the cube could be constrained so that it is half of the height of the beam, or a height that is always within the height of the beam, as shown on this image: