topic Re: Controling Instance parameter handles behavior in Revit Architecture Forum

Controlling Instance parameter handles behavior

ODP_MED_CRodriguez — Thu, 05 Feb 2026 20:15:04 GMT

Hello everyone

I'm trying to create a family with all parameters set to "Instance" but allowing "handles" to control only the overall length. The other instance parameters should be modified only through the "Properties" palette.

The issue I'm facing is that those "handles" affect multiple parameters at once, not just the length. Is there a way to prevent that?

I shared a family of a floor piece, where the length affects the finish thickness.

Re: Controling Instance parameter handles behavior

GaryOrrMBI — Wed, 04 Feb 2026 20:18:28 GMT

You're so close (reference planes set correctly), now just use the "Lock" toggle on the parameters to keep them from adjusting.

Without the lock the innermost of the three planes at the edges is staying in place as you adjust the length, which then increases the finish thickness where it is used on the ends, which, in turn, adjusts the Finish thickness at the top. With the lock that dimension will stay tied to the value that you set it to and will then move all three planes at the edge as a group, which will then maintain the desired thickness at the top.

Happy drafting,

-G

Re: Controling Instance parameter handles behavior

ODP_MED_CRodriguez — Thu, 05 Feb 2026 15:23:01 GMT

Hi Gary, Thanks for your response. I tried those options before, but I decided to give it a second try in case I was missing something, yet I still haven't had success. I locked the ones you indicated, as well as individually, or even all three, but I still couldn't get the top thickness to remain unaffected by the handles.

Re: Controling Instance parameter handles behavior

GaryOrrMBI — Thu, 05 Feb 2026 15:45:07 GMT

Take a look at these and see what might be different...

Version _2 is as I indicated in my first reply and Version _3 has a handle for the height as well as the Left and Right, and none of them affect the finish thickness when you drag the handles.

-G

Re: Controling Instance parameter handles behavior

ODP_MED_CRodriguez — Thu, 05 Feb 2026 16:55:54 GMT

Thanks, Gary. I saw what you did, but it indeed works because you converted the problematic parameter (Thickness Finish) to a "Type" parameter, but what I want to do is to keep all parameters as "Instance" to avoid creating more types of the family. (Sorry, maybe in the first example I sent, some parameters were set to "Type" precisely to avoid that issue)

If you put all the parameters under "Instance", you will see the problem. In fact, I have this issue with other families as well. I just sent this example in case there is a way to avoid it.

I applied a middle-term solution to similar cases before, by separating the controlling reference planes and then locking them together, but it's cumbersome to create many planes just for that. So, I wanted to know if there's a way to avoid the initial behavior.

Re: Controling Instance parameter handles behavior

GaryOrrMBI — Thu, 05 Feb 2026 17:22:46 GMT

Well, that one is on you, that Finish thickness parameter was a type parameter on the file that you uploaded and I started with 🙂

However, In the attached file are two ways of handling the issue and hit your target. You'll notice that I used another parameter with a formula to set the values for the ends (thus keeping them separate from the one used for the top and avoiding the conflict that way.

-G

Re: Controling Instance parameter handles behavior

ODP_MED_CRodriguez — Thu, 05 Feb 2026 18:23:15 GMT

I see it right now (the previous files, both families were the same) that chamfer control makes sense. Now I can have all parameters by instance. I was trying to control everything with ref planes, but I saw that sometimes additional restrictions are needed. I will apply that solution. Really appreciate it, Gary.