Revit wants to rotate line-hosted extrusions at certain angles

[AlexLibengood]

I am making a door hinge family using a face-based generic family template.  For the plate that moves around the hinge, I am using a Reference Line that rotates around the hinge point.  The plate is an extrusion hosted to that rotating reference line.

The attached family works exactly how I want to except when the "Opening Angle" parameter is set to 0 degrees.  For some reason when the angle is 0, Revit wants to rotate the extrusion 90 degrees and break the constraints.  It only does this at 0 degrees.  Every other angle (positive or negative works including 90 and 180).

I have seen behavior like this where Revit wants to flip reference lines at specific coordinates but I can usually find a way around it.  But I've never seen it want to rotate rather than flop and this time I can't figure it out.

Please help!

[EATREVITPOOPCAD]

Ok, buckle up for my ultra quick dirty solution. I saw similar problems posted similar to yours and seems like you would have to redo a bit of your family... Basically it breaks at 0 degrees but not at 0.1" degrees. But if you are ok with the user being able to input 0 degrees and have the family convert that input to 0.1 in the background you can do this...

I added a new instance angle parameter: Opening Angle User Input ,  which is inputed by the user as the name suggests...

then for your existing opening angle parameter I inputed this formula:

if(Opening Angle User Input = 0°, 0.1°, Opening Angle User Input)

[barthbradley]

Error says your zeroing out something. Zeroing out the angle deletes the Element.  Expand the Error Message to see what Element is being affected.  It'll list the Element ID so you can find it.  

...looks like you have an error with this Extrusion: 

[AlexLibengood]

Yep, I know it's that extrusion.  As my post states, Revit is trying to rotate that extrusion for some weird reason when the reference line it's hosted to meets a specific orientation (0 degrees in this case).  The rotation of that element breaks the constraints on that extrusion, hence the error.  But it should not be rotating the extrusion in the first place.

[barthbradley]

It's best to model the geometry that's moving with the angle in a separate family as Work Plane-Based, and then nest it into the family and host it to the Ref. Line that is rotating.  

[AlexLibengood]

Thanks. If we can't figure out why Revit is exhibiting this strange behavior, then this may be my only option.  Unfortunately, Revit starts acquiring other issues when dealing with angles that are slightly off axis...

[barthbradley]

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@AlexLibengood wrote:

Yep, I know it's that extrusion.  As my post states, Revit is trying to rotate that extrusion for some weird reason when the reference line it's hosted to meets a specific orientation (0 degrees in this case).  The rotation of that element breaks the constraints on that extrusion, hence the error.  But it should not be rotating the extrusion in the first place.

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I can see the family is breaking. I know why it's breaking and I can fix it so it won't break. Don't you want to do the same?  

[AlexLibengood]

Yes, this may be what I have to do.  I was hoping to avoid that because nested families tend to slow Revit down more, and creating a separate family just for a simple extrusion seemed like overkill.  I wish we knew why Revit is doing this so the nested family can be avoided.

[barthbradley]

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@AlexLibengood wrote:

Yes, this may be what I have to do.  I was hoping to avoid that because nested families tend to slow Revit down more, and creating a separate family just for a simple extrusion seemed like overkill.  I wish we knew why Revit is doing this so the nested family can be avoided.

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It's breaking because it's built wrong. 

Nested Families do not slow down Revit.  

[ToanDN · Accepted solution]

Create the plate as a sweep using the ref line as it's path, or host a
nested family on the ref line.

[AlexLibengood]

ok man, not sure why I deserve the attitude, but we have yet to identify a reason as to why Revit is breaking the constraints on a specific angle when all other angles work fine.  Using a nested family is indeed a work-around for this behavior and may be what I have to do, but it's not a reason for the behavior.

Also, it is well documented that nested families do indeed slow down Revit, and it's a good reason to avoid them if possible.

Straight from the horse's mouth: https://knowledge.autodesk.com/support/revit/troubleshooting/caas/sfdcarticles/sfdcarticles/Revit-Lo...

Also: https://forums.autodesk.com/t5/revit-architecture-forum/revit-family-keeping-them-workable/td-p/6908...

[AlexLibengood]

The sweep is a good idea!  I'll give it a shot.

[AlexLibengood]

The sweep works beautifully at all angles.  Thank you!  I wish I knew why Revit likes to flip things around at certain angles (almost always at an axis), but the sweep keeps my family simple and works well.  Thanks again!