Dimensioning Reference Planes to Reference Lines Causes Overconstrain Error

[libengan]

Is this expected behavoir for dimensioning reference planes to reference lines?

Example family attached.

The reason I want to use Reference Lines as the boundary is because then the drag handles will appear in 3D whereas if you only use Reference Planes, the drag handles only appear in 2D (see here: https://knowledge.autodesk.com/support/revit/learn-explore/caas/CloudHelp/cloudhelp/2018/ENU/Revit-C...)

Based on the contraints in this family, there should be no reason why I can't link a parameter to that dimension between the floating reference plane and reference line.  But yet the error perists.  Why is that?

[ToanDN]

Try this.

[Lachlan-JWP]

@ToanDNdo you know why the parameters associated with a dimensioned reference line can only be an instance (reporting) type?

[libengan]

Yeah, that's ultimately the workaround I've been using for this.  It works, but it's redundant to have both reference lines and reference planes for the same reference and can cause confusion in the future.  Also if you delete the "EQ" dimension on the reference lines, it will let you dimension to the floating reference plane.  It's like there is a hidden constraint somewhere that isn't visible to the user.

[ToanDN]

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@Lachlan-JWP wrote:

@ToanDNdo you know why the parameters associated with a dimensioned reference line can only be an instance (reporting) type?

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No. They can certainly be Type parameters.

[ToanDN · Accepted solution]

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@libengan wrote:

Also if you delete the "EQ" dimension on the reference lines, it will let you dimension to the floating reference plane.  It's like there is a hidden constraint somewhere that isn't visible to the user.

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Yes you can assign the parameter to the dimension between a ref line a a ref plane when you remove EQ EQ, but it will break when you change the Width parameter.

There is no hidden constraints, but the hierarchy that Revit uses: ref planes > ref lines.

[Lachlan-JWP]

ah so that's what I'd run into when testing this.

I could only make the parameter between the ref plan & ref line instance (reporting). Doesn't change if it's between the "EQ" or not. But you're saying that Revit won't allow a reference plane to be driven by a reference line?

[libengan · Accepted solution]

Yeah, what ToanDN said is mostly correct.  See attached family.

 If you remove the EQ dimension then the family will flex as shown without breaking.  However, the reference lines will move and the reference planes will not.  Indeed Revit sees Reference Planes as more important than Reference Lines.  Therefore it does not seem to be possible to have a Reference Plane anchored by a Reference Line.  Instead Revit will always try to anchor the Reference Line to the Reference Plane.