Edit Sketch with Newer Component Positions?

[Anonymous]

I'm working on the mechanical design of an electronic device. I have a sketch which defines the outline and cutouts of a printed circuit board (PCB) that I'll be creating as part of the design. After creating the sketch and extruding it into a model of the PCB, I've added and moved several components which are important to the mechanical design, like connectors and switches.

Now, I want to edit the PCB outline to account for the new components and locations. When I edit the sketch, I get the components that existed at the point in the timeline when I created the sketch, and their positions at that time. What I really need are the components and component positions at the end of my timeline, so that I can sketch around them and snap to their features.

Is there a way to edit an older sketch in the context of the end of the timeline, or will I need to create a new sketch to redefine my PCB features around new component features? Being able to edit an older sketch in the context of an arbitrary later timeline position would be of general use, but I would be quite satisfied if I could edit one in the context of the end of the timeline.

[davebYYPCU]

I am fairly sure you can have the best of both worlds here, the experts might contradict me, knowing more than I do at the moment, 

but to get going again, I would make a copy the original sketch then turn the original off, when you paste it, at the end if the timeline, rename it, and you should be able to "project / edit" with the details you want.

The caveat being I haven't seen the file, you will know if it will work or not.

Browny.

[TrippyLighting]

It would help seeing a screenshot. There is one workaround to it, but I am reluctant to give that advice without seeing your design.

[mike.tessier]

Hi @Anonymous,

Welcome to the Fusion 360 Forums!

There are a couple of things that you can do in this situation. The first is to do as @davebYYPCU suggested and make a copy of the original sketch and paste it at the end of your timeline. This should allow you to redefine the features you need to.

The second suggestion I have would be to turn off the capturing of your design history. I think this is what @TrippyLighting is hinting at, and he was correct to withhold the information because there is a pretty big risk associated with this method. When you turn off the design history, you lose the history of all components in the file. All components are saved as base features and if you need to refine any properties of the component or change the shape, (i.e. through editing the size/shape of a sketch that was extruded to form the component) you will not be able to.

To turn the capturing of design history off or on, right click the top most level of your design and select "Do not capture Design History" as shown in the screenshot below.

If you have any further questions or concerns, let me know! Hope this helps!

Cheers,

[TrippyLighting]

Nope, he's not 😉

But I have some experince in PCB desing in Eagle and Altium (Circut Maker) interfacing with Fusion 360.

You can actually "edit" a sketch without having to go back into the timeline.

The trick is to:

1 set thesketch to show

2. remove the dimensions on the outter perimeter of the PCB and make smart use of constraints. e.g if the PCB is rectangular, make sur to have it constrinad in a fashion that allows to maintain the shape while changing the dimensions.

Then the sketch elements that are not fully constrained due to the dimensions being removed  can be pulled into approximate position and later when editing the sketch precise dimensions can be re-applied. Cutouts also can be dimesioned and constrained to maintain shape without their position being dimensioned. that also should help dragging them into approximate position and later to be dimensioned precisely.

If you're not integrating fine pitch SMD/BGA boards with thou tolerances, that should work fine for most applications.

I would love to test this theory out but it'l be later tonight 😉

[TrippyLighting]

Here is a screencast showing what I mean. The dimensions in the sketch don't even have to be deleted. If the sketch dimensions are set to show, they can be edited without having to go into sketch edit mode, which moves you back into the timeline. The only thing that cannot be done is adding features to the PCB in the existing sketch, but it might even be wise to add these as separate sketches after the components are placed.

[Anonymous]

Turning off the design history sounds dangerous, but copy/pasting the sketch to the end of the time line sounds like the safest bet to me. I'd still like to see a feature to easily edit a sketch within the context of a later point of the timeline in order to snap to components that moved or didn't exist at the time of sketch creation, but the copy/paste technique sounds like a reasonable work-around without such a feature. I'll have to try it out next time this comes up, because I've already re-created the sketch to move my design along.

Thanks for the replies!

[mike.tessier]

There appears to be a post in the Fusion 360 IdeaStation, that requests exactly what you would like to see. I have linked to it here. The IdeaStation is the best place to go to request new features and functionality for Fusion 360!

Cheers,

[Anonymous]

Alas, that posting is archived, so it appears that I can't even add my "I Want This" vote.

[jeff_strater]

The reason this idea is archived is that it is, frankly, incompatible with the way Fusion works.  Fusion is a history-based modeler.  When you edit a feature or a sketch, you can think of it as time-travel.  We take you back to the point in time when this feature or sketch was created.  This is important, and necessary because Fusion has to prevent you from creating cyclical dependencies, and from creating references that are not possible to resolve.

As a simple example, consider this design:

In this design, there are two components, the yellow block and the blue cylinder.

If you then create a sketch where you select the top face of the yellow block, you get this:

if you then project the top of the blue cylinder into your sketch, you get this:

This circle in your sketch is now dependent upon the position of the blue cylinder component.  If you then move the blue cylinder:

Now, in order to compute that circle in the sketch (for instance if you change the size of the cylinder component) Fusion has to have the location of that blue cylinder at the point in time when the sketch was created, otherwise the circle will move.  And if you have other geometry in your sketch that references this circle, you could get wildly different results each time you moved the blue cylinder.  So, that is the basic reason why we move components back to their position at creation time.  Further, if Fusion were to allow you to edit this sketch with "newer component positions", you could then re-project the same edge into the sketch, at a different position.  Hopefully it is obvious why this would be a bad thing.

Now, having said all that, there are a couple of options for you:

1. You can drag sketch geometry without editing the sketch.  Just make the sketch visible, and you can drag, even while not in sketch mode
2. You can right click on the sketch and choose "Show Dimensions".  This will make dimensions in your sketch visible and editable.

Both of these will let you do some limited editing without the rollback.  You just cannot create anything new

Finally, you can reorder the sketch, or the component moves that you are concerned about.  If you do not have any references that prevent it (like the above example), you can drag the sketch in the timeline to a new place in history.  Fusion will block you from dragging it to an illegal point in history.

Hope this clarifies things a bit for you.

Jeff