Timeline and constraints problem

[Anonymous]

I'm having difficulty constraining a sketch of a lower number to that of a higher number.  It seems the Timeline prevents me from doing so, as when I go to edit the older, lower numbered sketch, the newer sketch which I want to constrain to disapears.  Because according to the timeline, it doesesn't exist yet. 

When in similar situations with other features, like forms, I have been able to drag and move the form in my timeline, solving the "doesn't not exit yet" problem.  I have tried draging the sketches in the timeline to change the order, but this not seem possible. 

Is it just me, or does this notion of the Timeline, as it's iterated in Fusion 360, seem to conflict directly with the concept of parametric CAD? 

I reaize I could delete the older sketch and redraw it.  But to me that is the textbook anthesis of parametric CAD.

I'd be grateful is someone could show me how I can solve my problem without deltetion.

Thanks much

[Anonymous]

Hi Peter, you can rearrange a sketch in the timeline, provided the relevant dependencies are removed.  To do this, go to Edit the relevant sketch, do a drag window/box select of all the geometry in your sketch, right click and see if Break Link option appears.  If it does, click it and that will turn any purple "dependant" geometry back to regular sketch geometry color.  Then you should be able to drag the sketch back or forward in timeline (note there is sometimes a delay while Fusion is checking if such a rearrangement is allowed).

Another option you have is to in Model workspace go to Create > Create Base Feature, then while in that direct modeling mode there is no "temporal" nature, and when finished go to upper right Finish base feature button.

Jesse

[jeff_strater]

Thanks, @Anonymous.  I wanted to comment on the "antithesis" comment.  All parametric CAD systems that I'm aware of have this "time-travel" aspect to them.  If you edit a feature (or sketch, or work geometry) that was created earlier in time, the system must prevent you from referencing dependent geometry that was created later in time.  We have to prevent dependency cycles.  You cannot have a line in sketch 1 that is dependent on a line in sketch 3, which is also dependent on a feature created from a line in sketch 1, etc.  Now, you could argue that the current mechanism (rolling back to the state of the design when a sketch is edited, hiding later-created items) is somewhat of a big hammer for this.

Jesse's point, though is correct.  If there are no dependencies in sketch 3 on geometry in sketch 1, you can reorder sketch 3 in the timeline to come before sketch 1, and therefore create that reference

But, I think that you will find very similar behavior in all modern parametric CAD systems.  Parametric design does require some forethought.  You have to plan your modeling activities, and think a bit about what component, bodies, sketches, features, etc you will need for your design.  And sometimes you will get it wrong, and you have to backtrack a bit to make some changes in your plan.

Thanks for the comments,

Jeff Strater (Fusion development)

[Anonymous]

Thanks @Anonymous, I couldn't find the "Break Link" option, but I also haven't been able to reproduce the problem since.  I've tried creating the Base Feature, but I still can't constrain sketch 1 to it without reordering.  Maybe I've musinderstood.  

@jeff_strater, I do want to thank you and the rest of the team for Fusion 360. I would like to see it flourish! Please understand that my experience is with Catia, where there is no notion of a timeline other than the undo history. Any sketch, or other form, can be constrained to that of any other epoch without preparation. You'd like to constrain your first sketch to your 100th? No prob. "Edit Sketch 1 > Constrain> Exit Sketch> done!"

Because of this freedom, design can be done _in the program_, not necessarily before. And I think that's what Fusion 360 is striving for. I don't see it as a tool that simply settles for just being used to input completely realized designs from a draftsman. I think when you're designing something you've never made before, it's not realistic to have it fully realized in your mind...unless your the Mozart of design. I certainly don't work that way.

As a feature, I don't understand what value the timeline brings to the user. Granted, because of the approach I am used to, I've done a fair bit wrestling with it to achieve my design goals as of late. I could be completely misunderstood about it's function, but it only seems to get in my way.  I can't imagine someone saying, "Thank goodness the timeline was there!" 

In terms of UI, it's somewhat redundant, since every sketch and body is already represented in the tree. There may be a better section of the forum for this, but, I'd love to see all of the geometry and constraints of a sketch listed in the tree, as an expandable sub-component of the sketch. And a pony! 🙂

Anyway, I do love Fusion 360, I just hope that the timeline dies in a fire. 🙂

[jeff_strater]

Hi @Anonymous, thanks for the follow-up post.  I think we may have just what you want.  If you change your preference to "Do Not Capture Design History (Direct Modeling)", your designs will not have a timeline, and will not capture any history.  It's a way to get your "dies in a fire" wish, sort of.

This is what we internally call direct modeling.  You are always just interacting with the model in its current state.  I'm not familiar with Catia, or what you can do with it, so I am not 100% sure that this will be exactly what you really want, but it sounds like it might be close.  However, the opportunities for associative edit in this type of design are very limited, so sometimes it becomes difficult to make the exact edit you want, once the model gets to a certain size.  But, give it a try and see what you think.

Regarding 'I can't imagine someone saying, "Thank goodness the timeline was there!"', that's a bit ironic from our side :).  Fusion was born as just a direct modeler, no history, no timeline.  We spent two years of our lives putting the history-based editing in there.  So, hopefully, there aren't too many of you out there who don't like it! I think that once you use it a while, you may come around.  It can be a very powerful tool, but admittedly takes some planning to use it effectively.  I'm also glad that we didn't just abandon direct modeling, so that option still exists if you want it.

Thanks for your insightful comments.  We are happy that, even with your frustrations, you do find Fusion compelling.  We appreciate posts like this.

Jeff

[Anonymous]

Hi @jeff_strater,

Thanks for your suggestion about using the Direct Modeling mode.  Unfortunately, that's not a solution for me, although I see it does remove the timeline.  In that mode I'm able constrain earlier geometry to later, but then I lose the ability to drive my designs with parameters.   What I'm used to, combines the aforementioned aspect of Direct Modeling _with_ parameters.

Believe me, I fully embrace parametric modeling, I just know that someone figured out a way to do it without the "time-travel" aspect.  And it is awesome!   I hope that you folks consider it, and that it doesn't require something as drastic and low level as a different kernel, or throwing away 2 years of codebase.   Parametric modeling does not have to be synonymous with a timeline feature.....please understand my experience tells me so.  I daresay you wouldn't feel any irony if you also had this experience.   Please know that I want to celebrate your work, not belittle it.    I teach Fusion 360 at the makerspace I'm co-founder of.