Sunday, March 10, 2013

Reference Plane Order

This is subtle. When you draw reference planes the order they were created plays a role in how a parameter will move them later. Draw two new vertical parallel reference planes, draw one on the left and then next to the right of the first. Add a dimensions and assign a label (parameter) to the dimensions. Flex the parameter value and watch the reference plane on the right move. If you have a lot of reference planes it can get confusing but this underlying behavior is lurking there.

You can force certain behavior by pinning reference planes, locking dimension or using the EQ constraint to force them to move equally about a center reference line. Like I wrote, it is subtle. Just keep it in mind while you do your family editing.


Anonymous said...

Any tips on getting EQ to respect the position of the center plane? Sometimes even if it is the first created of the three, and even if it is locked in place, it still moves.

Steve said...

Take care to place the reference planes equidistant to begin with, add your dimension string, click EQ.

When you select one of the reference planes you should see an anchor appear above the dimension string, usually at one end.

You can move this anchor to the middle reference plane. This will cause the outer reference planes to move and leave the center one in place.

You can also pin the middle reference plane.

Alfredo Medina said...

The "rule" that I have observed is that, assuming that two reference planes are unpinned, and you create a dimension between them, if you change the dimension Revit will always move the plane that is newer; the older stays still.

Erik said...

I often use a "Half" parameter rather than an EQ constraint. For example, if I want Paramter "Width" to flex equally from the center I will create a "HalfWidth" parameter that has a calculated value of Width/2. That parameter controls ONE of the planes in question and the other follows along.

I got into that habit early on when I noticed some weirdness in the way reference planes behaved when EQ constrained.

Erik said...

Shoot, forgot to follow replies.