Monday, 7 June 2010

Shape Handles (Dragging Grips) and Instance Parameters

Using Instance Parameters usually means that when you load your family into your Revit project you see blue grips or arrows at the ends of the instance elements.

When setting out geometry from a Level in an elevation view, sometimes the Shape Handles (Grips) don’t appear. Why? I have no idea, but I found the solution by adding a reference plane on top of the level line and locking them together. Dimension to the reference plane instead of the level line and the shape handles appear correctly.

In the example below I used Generic Wall Based Family which has a Reference Level at the base of the wall. I’ve added a vertical sweep constrained by a reference plane at the top. The Height Parameter is dimensioned from the reference level up to the reference plane and is an Instance.

Here it is loaded into a project, notice it is selected but there is no shape handle.  I can access the instance parameters and adjust the height this way but that's not how i want to control this object.  I want to click and drag to see the object increase in height.

In this example to the left, I have added a reference plane in the family and aligned and locked it to the reference level.

I recreated the Height Parameter and this time dimensioned it from the lower 'Reference Plane' (you may need to TAB to cycle through until you can select it).

<-- Here it is loaded into a project again but this time I get the Shape Handle!

Note: Some Families already have a reference plane hidden along the same line as the Reference Level so check first to see if one exists and then make sure you dimension to the plane not the level.

Other reasons for not seeing shape handles appear are due to a string of instance parameters being joined together i.e. There are too many variables for Revit to work out which parts can be dragged/stretched!


Anonymous said...

Nice post, it worked great!

Anonymous said...

You just saved me so much time... awesome :)

Anonymous said...

Does this work for a generic annotation family and stretching a detail line? I can't seem to make it work.

Chris Senior said...

Yes it should work fine using instance parameters

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