Not satisfying constraints - please justify this

[simonrogers85]

Hi all,

In the attached 2 images, I have shown 3 reference planes. Quite simply I am trying to set an overall Width parameter, and I want the reference planes to be centred equally.

I tried the method shown in image 1 attached using the EQ dimension option however always got 'constraints not satisfied' errors.

I resorted to the option I showed in Image 2 however I don't understand why option 1 never worked. After alot of tinkering around I found that if I did the constraints in different order sometimes it would work. Could someone please clarify this simple yet troublesome problem.

Cheers.

[arqt49]

Do you have constrains in other views?
Can you post the trouble file?

[jeh.212740]

The first image is the way i would do it, i have noticed that from time to time if i want my reference planes to be eq eq, i will draw one and mirror around the center reference plane then constrain with eq. Then dimension the overall and you should be good. Another side note is to check to see that the width parameter has a value prior adding the parameter to a dimension. I hope this will help.

[btrusty]

i wonder if 'constraints not satisfied' is a translation from another language for "over constrained"

[simonrogers85]

The problem is that it tries to change the width by keeping the left hand plane still, therefore changing the width will force them not to be EQ and will create the error.

The attached image shows what happens when both planes are EQ at 377 from centre, and I try to add width parameter which is set at 1000.

Revit file is also attached. How can I make it so the left plane is not the 'dominant' plane?

Cheers.

[Scott D Davis]

Place the dimension that will be the EQ dim first, then place the overall dimension. Then change the overall dimension to the labeled parameter dimension. If your parameter value is set to 1000, then make sure the dimension reads 1000 between the ref planes before you add the label to avoid the error as well.

[bbeck]

What Scott said or accept that the "constraints not satisfied", parameter is removed leaving just a dimension, then add the parameter immediately back after that initial "flex".

[david.kingham]

You can also get around it by unpinning the center ref plane

[ron.sanpedro]

You can also get around it by unpinning the center ref plane

Given how Revit manages insertions, is there really any value to pinning the origin defining ref planes? Seems like an unnecessary constraint, and one step closer to over constrained before you even start any work. Kinda makes me want to review all the templates before rolling out 2011 and just unpin stuff.

Gordon

[Scott Womack]

Given how Revit manages insertions, is there really any value to pinning the origin defining ref planes? Seems like an unnecessary constraint, and one step closer to over constrained before you even start any work. Kinda makes me want to review all the templates before rolling out 2011 and just unpin stuff.

I understand your pain, however, pinning the two reference planes that form the insertion points of a family can actually make them work smoother, provided you learn to work with them. I have learned to use a "Half Dimension, rather than the EQ system, and this seems to work smoother on very complicated families.