Thanks @davebYYPCU for all those details. I'm a bit confused by some of it, so I'm gonna try to navigate through it.
Note, Sketch "Offset A (error)" was broken without me noticing it. Looks like it breaks if I change the reference... I rebuilt the Sketch (Offset A (good)) as originally intended: Start Sketch > Select Front Face > Offset Line Feature > Select Front Edge > (Dimension) > Done.
As opposed to Sketch "Offset B", where I project the front edge/profile first, and then offset the projection.
I think there are various Project meanings within your file. (latest with offset B fully constrained whilst Front sketch remains unchanged, changes breaks the sketches.)
You would need to define what you want to do.
(As a demo file has some interesting outcomes - prompting a small Rant)
I'm trying to make sure that if I only change dimension on Sketch "Front", the changes occurring on the 3D geometry will be reflected in the projection I create in other sketches (≠ breaking)
The fillet on the Loft, transfers to both subsequent sketches as Splines. Unconstrained splines, can allow weirdness you are seeing.
Not sure I understand why those would be considered unconstrained splines? But maybe you're talking about the broken sketch "Offset A (error)".
Offset Sketch A has no offset dimension, but the mirror in Front Sketch is transferred in.
Once again sorry if the sketch "Offset A (error) was confusing.
Outline profile is projected by preference setting. (single profiles - see below)
Couldn't find anything in the preference settings.
You say that you projected the outline into Offset B, purple lines, correct, then you offset the outline for the black internal profile, all good, except when you created the sketch (on the face of the body or Sketch A profile,) it too was projected by Fusion and the outline curves are purposefully hidden to avoid clutter, but doesn't avoid confusion.
Select Other on the Offset B blue shadings, and you will find two profiles listed, where we humans think and expect there should only be one. ( @jeff_strater you listening? Create sketch on body the immediate light blue shading is not obvious, (unless you hide the body,) I am used to this now but OP has not even figured it out yet.)
I think I understand what you're desbricing but I don't understand how this is the issue.
Now because Fusion has two / three profiles and splines to play with you lose control of the file.
Same here, not sure why this is the issue, I mean my reference (front edge of the 3D geometry) is what it is. I should be able to project it 100 times and have the 100 projection update if I change the 3D geometry...
Two choices, either create sketch on Offset / Origin planes or don't project twice.
I sepatered the different ways, plans, profiles and sketches to achieve what I want to make sure we understand each other. See below.
So I reproduced the issue I was running into without having my reference and my projection on the same plan/profile, just to make sure that's not what is causing the issue.
Test #2: I only project the front edge of my geometry.
Test #3: I project the front edge of my geometry first (since I realized that I can't directly offset the front edge since I'm not on the same plan/profile anymore), then I offset the projected line to the desired distance.
But when I changed the dimension/design of the 3D geometry reference, Test #2 updates properly while Test #3 breaks, more precisely the projected lines update properly, but the offset of projected lines don't...
Please let me know if you observe the same issue, and if you know why it doesn't work.
Thanks again!
