Changing the source of an offset work plane

[jyager]

To simplify, I have a vertically rectangular frame with internal frame elements at two separate levels based off offset work planes.

The lowest internal plane is offset up from the XZ plane and the highest internal plane is offset up from that lower plane. In hindsight I should have based that second plane also off of XZ, or off the height extents plane at the top of the rectangular box.

So that top third section of the box CAN be sized with a little math, but if I change the lower 2/3  of the rectangle it's going to want to follow that lowest internal plane (which I can tweak again to get what I want)...is there a way to just change the source of that higher internal planes source plane? Like switching it to XZ or the height extents?

[cbenner]

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@jyager wrote:

To simplify, I have a vertically rectangular frame with internal frame elements at two separate levels based off offset work planes.

The lowest internal plane is offset up from the XZ plane and the highest internal plane is offset up from that lower plane. In hindsight I should have based that second plane also off of XZ, or off the height extents plane at the top of the rectangular box.

So that top third section of the box CAN be sized with a little math, but if I change the lower 2/3  of the rectangle it's going to want to follow that lowest internal plane (which I can tweak again to get what I want)...is there a way to just change the source of that higher internal planes source plane? Like switching it to XZ or the height extents?

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You can redefine work features.  Simply right click on it either in the graphics window or the model tree and select Redefine.  Select a new source for it and redefine your offset distance as needed.... now, that's the easy part.  Anything the references that plane may need some repairs when the plane is redefined.  Hard to say if or what you will need to fix without knowing the structure of your assembly.... but be prepared for some sketches or other features to fail and need some redefining of their own.

[jyager]

Chris,

 I actually tried the redefine feature, but it's not letting me select either of those two planes. Maybe this PDF helps clarify things.

I'm trying to hold that top at around 16" but the lower sections may vary until equipment is finalized, so I'd like to lock that upper section in and forget about it instead of retweaking it every time the mid section changes.

[swalton]

It sounds like you are tangled in your parent-child relationships with the work planes. Components in assemblies don't have parent-child relationships, but it looks like workfeatures do.  Treat the problem like re-defining features and sketches in an ipt file.  You can't define a parent to be dependent on a child because the child does not yet exist.

If so, you may need to take several steps. Redefine the child planes so that they are only dependent on the origin work planes.  Then you can redefine the workplanes so that the dependencies follow your requirement of maintaining your 16" dimensions.

[cbenner]

This doesn't help you right now, but I will make the comment that I used to get into this all the time with multi leveled frames.  I stopped using work planes to define the upper levels because of these types of headaches, and now I use 3D sketches for just about all of the upper frames I build.

[LT.Rusty]

Another thing you can do - and I've done this from time to time when I have layouts of things that I know are going to be changing a lot - is to create an additional part file that uses sketch geometry.  You can simply edit the sketch dimension in the layout part file - all that's in it is a sketch or two as needed - to change the location of your planes.  Set the item BOM type to Phantom, so it doesn't screw up a parts list.  When you're done with it, or if it's getting in the way, simply make the part invisible.

See the attached Inventor 2013 files for a more clear visual of what I'm - probably badly - explaining.

[jyager]

Thanks guys, those seem like better solutions. I think I need to just make sure to avoid parent/child relationships with work planes in general.