Forums >> Revit Building >> Tips & Tricks >> Trick for Offsetting Parameter Both Directions from Centerline

marmiketin1

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Joined: Wed, Aug 19, 2015
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The problem is that with parameters you cannot use negative values.

I was trying to make a curtainwall mullion in which I could change the centerline position so that I could align specific edges of differing mullion sizes. Mullion profiles however do not have obvious top/bottom and left/right positions as the profiles follow the curtain grid which can be drawn in many directions. So in order to overcome the issue of not knowing which side of center I will need to offset before loading into my project and testing I created a simple way to accomplish both.

Start by drawing 2 reference planes left (or right) of the centerline. Then add a dimension from the centerline to the left most reference plane and make it a parameter labeled 'left offset'. Next add a second dimension from the left most reference plane to the remaining reference plane which should be to the right (this is important) and make it a parameter labeled 'right offset'.

Now you have two offset values which can be changed, one for the right and one for the left. If you set both to zero the object will be centered. If you change the left offset to 10 and keep the right offset at 0 the object will be offset 10 units to the left.

Hope this is helpful for some.

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Shatner86

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Joined: Fri, Feb 24, 2012
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Hey Marmiketin1,

Thanks for the post! Would have been super handy for me a few years back when I first needed to do this. However there is one thing I did on top of this which I thought I’d staple onto this post.

Context: I work in FF&E and not curtain walling, so might be a bit different but the issue I have with "right" and "left" dimensions being editable is that they are open to abuse/confusion etc. from project environment users. So, I create a couple of small formulas to handle it.

Within your Centreline Offset parameters you create the following formulas:

if(Offset > 0 mm, Offset, 0 mm)

if(Offset < 0 mm, abs(Offset), 0 mm)

What the "abs" does is convert a NEGATIVE value into a positive. That way, if the user inputs a negative number/length, say -1200mm, the parameter/length/dimension constraint containing the formula with "abs" will accept and then convert the input. Thus, moving the object in the correct direction. With "-1200mm" being less than 0, the other dimension will ignore it and remain at 0.

Hope that makes sense.

Kind Regards,

Shatner86

-----------------------------------

"Try not to become a man of success, but rather to become a man of value"

-Albert Einstein

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jmqrsq

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Joined: Thu, Oct 20, 2005
168 Posts

Old thread I know, but hopefully one of you can respond. Specifically Shatner:

I am not 100% following where these formulas would go in this example. Can you elaborate which parameter would get what formula? Thanks in advance

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jamestrive

Joined: Sun, Sep 22, 2024
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Consider using Shared Parameters between models so the offsets can be driven from a single shared parameter set, making it easier to test different offsets across multiple views/designs.

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