Plumb and square cut on a parametric truss family

[DrakeCanyonArchitecture]

I'm just starting to get into the cooler side of building families. I am building a parametric truss starting from the generic model, I know there is a truss family template but I'm just interested in the display aspect of the family and not worried about analytics.

Anyway, I have my truss working the way I want it to (adjustable span, overhangs, pitch) with the exception of being able to change the truss tail from plumb to square cut. The top chord is an extrusion locked to the reference planes. I used a reference line for the tail so I could get it to pivot. When I lock the truss tail to the reference line, then try to adjust the angle, I get the error "Constraints are not satisfied". Any ideas why this is happening? Below is a screenshot and I am attaching the file as well. 

[Redrunner92]

How many different tail cut types do you want? If you only want two options, a square cut and a plumb cut, you can use visibility toggles combined with yes/no parameters to make a simple toggle.
To do this, copy the top chords to the clipboard (don't immediately paste them), then assign a yes/no parameter to the current top chords' visibility property (let's say they are the plumb cut top chords) and call it Plumb Cut or something similar, ensuring it is a Type Parameter. Make sure the profile for the plumb cut sweeps' sketches are locked at 90 degrees (I suggest using sweeps rather than extrusions for this case) by making each profile's work plane vertical, not perpendicular to the sketch line.
Next, paste in the same place the copied top chords. In the sketch of each top chord's sweep profile, make sure the profile stays oriented at a right angle to the path line by setting the profile's work plane perpendicular to the sketch line. Then assign these recently-pasted top chords' visibility properties to a new yes/no parameter called Square Cut or something similar, ensuring it is a Type Parameter.
Finally, in the Family Types menu, make two separate types: one named Plumb Cut and the other named Square Cut. Then set the toggle boxes accordingly so when the Square Cut parameter is checked, the Plumb Cut is unchecked. You can do this by inserting this formula into one of the two parameters' formula fields, in this example below you would place it in the Square Cut formula field:
not(Plumb Cut)
I'm not certain this will work, but it's worth a shot.

And I'm aware it isn't the approach you are trying to do but it may give you the end result you desire. Just an attempt if you want to go this route 🙂

[DrakeCanyonArchitecture]

@Redrunner92, thank you for your suggestion. I hadn't thought about (and haven't experimented with) the option of creating different types. I will need several types actually such as scissor trusses, stubbed trusses, etc. so maybe it would be best to create several types. The main reason for needing the plumb cut is in the case where the truss sits in a girder. I appreciate the input!

[Redrunner92]

I hope that direction works for you! Like I said, I'm not certain all the steps will work but it's worth a shot.

Also, after mulling it over for a bit, you may be better off making the two yes/no parameters as Instance parameters since I'm sure you will have many types.

I suggest making different families for different constructions of trusses (scissor, shed, typical gable, etc.). Trying to put them all in the same family may make an unnecessarily large quantity of parameters and therefore a daunting Type Properties menu when loaded into the project. In contrast, different families could, if built in similar ways, be easily swapped out when needed.

Again, just some musings for you to consider.

[barthbradley]

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@Redrunner92 wrote:

How many different tail cut types do you want?

Let's not forget about the "Boot Cut".  😁

[DrakeCanyonArchitecture]

@barthbradley, and parameters for slippers, skates, galoshes...