topic Re: Logic behind basic constraining in Revit Architecture Forum

Logic behind basic constraining

tuomas.einamoV2MEV — Tue, 20 Feb 2024 12:03:10 GMT

Trying to go back to Revit after a long break as I have to make a ton of families for Revit in the near future. I am having a hard time grasping the logic with the drafting.

For example if I am creating an extrusion in the ref level. I start by drawing a rectangle with one side aligned with the horizontal reference plane. I then lock the alignment of the line with the horizontal reference plane by clicking the red lock symbol. Then I click the measurement on the left side of the rectangle, measuring the depth of the to-be extrusion. When I change the value, I would assume the rectangle would stretch from the end that is not constrained to the reference plane, but no. I get an error when Revit tries to stretch the rectangle from the constrained side. Why?!

What is the logic behind this? Is there a tutorial that could help me understand this?

I know this might not be the correct way of working with Revit but nevertheless I would like to learn the logic behind the way the program works.

I have worked with other cad programs for years and maybe I am stuck on a different logic.

Re: Logic behind basic constraining

blank... — Tue, 20 Feb 2024 13:41:48 GMT

Can't recreate (see video).

Re: Logic behind basic constraining

pedruccioli — Tue, 20 Feb 2024 14:40:32 GMT

From your description, seems like you're trying to change the value while selecting the constrained line. In this case, because you're in Edit Mode, Revit will try to move the line you have selected. If you create a dimension and label it outside edit mode, Revit will move the unconstrained side as usual.

Re: Logic behind basic constraining

RSomppi — Tue, 20 Feb 2024 15:07:31 GMT

As things get more complex than this example, it's advisable to use reference planes to constrain the geometry. For something this simple, (which should work as you describe) it may seem like overkill but it's good practice.

Re: Logic behind basic constraining

Alfredo_Medina — Tue, 20 Feb 2024 16:17:19 GMT

I recommend you to watch this tutorial, to understand the sequence of steps to make a parametric family:

https://youtu.be/RyP9nOTpXo0?si=CUCJ_hqDb4ttwMAN

Re: Logic behind basic constraining

handjonathan — Wed, 21 Feb 2024 13:41:38 GMT

Hi @tuomas.einamoV2MEV

Thanks a lot for posting your question to the forums!   Have the solutions suggested by @Alfredo_Medina @RSomppi @pedruccioli helped with your issue?
 
We look forward to hearing back from you with more information so we can help you as a community! 