How to work with multiple sketches?

[Anonymous]

This is most likely a case of me not understanding the design of Fusion 360.  I created a sketch, call it bottom and added some lines to it.  I created another sketch call it side, and added some lines to it.

When I work on side, I can see, reference, and constrain from side to bottom.

When I work on bottom, it's as if side doesn't exist.

Is there a way to work around this, or should I just do all of my work in a single sketch?

[laughingcreek]

no, you shouldn't do all your work in one sketch.

what your seeing is a result of where the sketches are in your timeline.  edit a sketch, and the design rolls back to that point while you edit.

post your first sketch and a pic of what you want to do and I'm sure you'll get some pointers.

[Anonymous]

It's not a specific sketch or a specific task.  It has been recently suggested to me that I try doing multiple sketches, rather than a single monolithic sketch.

When I do all my work in a single sketch, I can freely reference between the different parts of my sketch, no matter what order they were created in.  If I separate some of that into another sketch, it does not appear the same holds true.  If this is the case (and its not just me missing some setting, or clicking the wrong button), then I lose an essential feature switching to multiple sketches.

Is it possible to prevent the "rollback" when you edit a sketch?

[g-andresen]

Hi,

If you think that you have to fit everything into one sketch, you do not need to explain this here.

Just do it and gather your experience.

günther

[Anonymous]

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If you think that you have to fit everything into one sketch, you do not need to explain this here.

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Please read my posts, I don't say this at all.  I am exploring the idea of using multiple sketches because it seems to help quite a bit with organization, however in doing so I ran into a situation where referencing one sketch from another is dependent entirely on creation order.  I posted here to ask if I was missing something.  I don't have any preference as to a single or multiple sketch work flow, but I do require being able to freely reference objects.  Is there a way to allow multiple sketches to do this, or should I stay with a single sketch if I want this functionality?

[laughingcreek]

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@Anonymous wrote:

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... but I do require being able to freely reference objects   

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 The perception that you can't may change as you gain experience and adjust your workflow to fusion.  That may require working through examples with others.

...Is there a way to allow multiple sketches to do this..

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No.  The only way to get the "functionality" your asking about would be to turn off the timeline and go to DM mode.  but then you loses all the parametric capabilities of fusion.

... or should I stay with a single sketch ...

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completely design dependent.  but you'll be very limited in complexity if you stick with one sketch.

[chrisplyler]

Multiple sketches is quite handy. There is a lot of modeling achieved via multiple sketches that just couldn't be done with only a single sketch.

However, a "reference" (we call them dependencies) cannot exist to something that doesn't exist yet. You can make dependencies from Sketch2 to Sketch1, but not the other way around. It just takes a little bit of forethought and thinking through your design intent. There is nothing I can't model due to this "limitation."

[Anonymous]

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@chrisplyler wrote:

It just takes a little bit of forethought and thinking through your design intent. There is nothing I can't model due to this "limitation."

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I get it, for many that might work; however that isn't a design paradigm that works for me.  I design as-I-go.  I have a very rough idea of what I want, and I start to sketch. 

It sounds like the multiple sketch paradigm is not the flow for me.  I appreciate the input though.

[chrisplyler]

Fair enough. I find it useful to embrace multiple methodologies, instead of limiting myself to one. You never know what you might model in the future. Good luck.

[scottmoyse]

On a design by design basis you can do this:

If you want to work like this permanently, under you name in the top right corner, select Preferences. Then change this setting:

[davebYYPCU]

I use a hybrid method, if there is a reference in the future, copy or create it again into the early sketch.

Might help....

[Anonymous]

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@chrisplyler wrote:

Fair enough. I find it useful to embrace multiple methodologies, instead of limiting myself to one. You never know what you might model in the future. Good luck.

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I wouldn't say that I am limiting myself, so much as refining.  I know what methodologies have worked for me over the years, which ones I enjoy, and which ones I don't.  A lot of it depends on purpose and scope.  I am not an engineer in a manufacturing plant that has a specific part that needs modeled, and a deadline.  I am a hobbyist that loves to create and enjoy the journey.  I get enjoyment out of an empty canvas and an end goal.

[Anonymous]

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@scottmoyse wrote:

On a design by design basis you can do this:

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While I would love to work in that mode, I rely heavily on parameters; which I gather I would lose if I went this route.  I honestly think every single dimension on every model I make is parameterized, maybe thats just the software engineer in me, but I find it to be one of the most useful features in Fusion 360!

[dankG2KYJ]

Since you rely heavily on parameters and in case you haven't seen it....If you click "Show dimension" on your sketch icons, you can create/edit functions between two sketch dimensions while they are both visible. You can roll back the timeline and it will still reference Sketch 1 ->Sketch 2 when you edit your first sketch. Might help a bit.  

[scottmoyse]

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@Anonymous wrote:

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@scottmoyse wrote:

On a design by design basis you can do this:

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While I would love to work in that mode, I rely heavily on parameters; which I gather I would lose if I went this route.  I honestly think every single dimension on every model I make is parameterized, maybe thats just the software engineer in me, but I find it to be one of the most useful features in Fusion 360!

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Well.. you can't have your cake and eat it too I suppose. Parameters need history. You might just have to get used to working in a structured way with sketches in your timeline.

You can create a Base Feature and sketch within that... it gives you access to your parameters. But it just copies the value of the parameter into the sketch dimension. It doesn't maintain any kind of link.

[chrisplyler]

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@Anonymous wrote:

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I wouldn't say that I am limiting myself, so much as refining.  I know what methodologies have worked for me over the years, which ones I enjoy, and which ones I don't.  A lot of it depends on purpose and scope.  I am not an engineer in a manufacturing plant that has a specific part that needs modeled, and a deadline.  I am a hobbyist that loves to create and enjoy the journey.  I get enjoyment out of an empty canvas and an end goal.

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Same here. I don't make anything with Fusion. I just wanted to teach myself some 3D parametric CAD for fun. That was a couple of years ago, and I've done NOTHING with it BUT learn it and practice it and participate here in the forum. MOST of the stuff I've modeled has been in an effort to work through a problem somebody else came here to the forum with.

The inability to make reference to things that don't exist yet, in Fusion, is not limiting to the modeler. It is only limiting if you aren't willing to think around it. If I'm halfway into a model, and realize I want something from the past to reference something from now, then I think about how I should have done it differently before I reached this point. It didn't take long to develop the little mental habit of diagnosing and accounting for such possibilities before I even get that far.

Many of the very best modelers - some of the ones that Autodesk recognizes as "experts" and who have been invited to speak on various modeling strategies - will tell you that they often make a "first draft" model, and then a final model that is done better. It's no sin to discover an obstacle halfway into a project, and start over to correct for it. I'm most often able to account for the past-referencing-the-future issue by revising something...maybe making that future thing that needs to be referenced earlier in the process. Occasionally this correction can be made with a simple reordering of timeline steps.

Anyway - if you are interested - I would be happy to take a look at a project you've worked on where you had this problem, and offer ideas about how it might be done without the problem. Perhaps working through it like that might help you see how to avoid it in the first place?

[Anonymous]

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Well.. you can't have your cake and eat it too I suppose. Parameters need history. You might just have to get used to working in a structured way with sketches in your timeline.

You can create a Base Feature and sketch within that... it gives you access to your parameters. But it just copies the value of the parameter into the sketch dimension. It doesn't maintain any kind of link.

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That doesn't make any sense to me.  Variables should not be dependent on history. 

@chrisplyler I think the problem is less "The inability to make reference to things that don't exist yet" and more of a why does travel back in time to when the thing did not exist in the first place?   I understand how moving through the timeline could be a useful feature; what I don't understand is why it's forced when you edit a sketch.  

I appreciate the outlook, but I am not a modeler (not even in the hobbyist sense), nor do I intend to be one.  I may model a part today, and then another in 1-2 years from now, or I may make 2-3 parts this month, it depends entirely on if I need a part for something and it doesn't already exist online somewhere.

To be clear, these are me wondering out loud why these choices were made, not me demanding (or even asking) them to change how anything works for my use case.

[TrippyLighting]

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@Anonymous wrote:

I appreciate the outlook, but I am not a modeler (not even in the hobbyist sense), nor do I intend to be one. 

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CAD isn't something you pick up over a weekend and then casually "model" something every few months. Have you completed any of the tutorials in the Learn & Support section?

Once you've done so you'll have a better understanding of workflows and some of your questions you'll be able to answer yourself 😉

[chrisplyler]

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@Anonymous wrote:

@chrisplyler I think the problem is less "The inability to make reference to things that don't exist yet" and more of a why does travel back in time to when the thing did not exist in the first place?   I understand how moving through the timeline could be a useful feature; what I don't understand is why it's forced when you edit a sketch.  

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I'm just guessing here, but I'll bet one strong reason is to prevent the user making circular dependencies. Imagine you make something in Sketch2 dependent on something in Sketch1. Then you edit Sketch1 and make something dependent on Sketch2. Boom...circular dependency that makes Fusion sit there and calculate in an infinite loop, causing a virus to spread, stores to be looted, and factories to be burned down.

[jeff_strater]

@chrisplyler is exactly right here.  The "time travel" here is to prevent circular references.  There is a bit of UI around "take me back to when this sketch/feature was created", but, TBH, that is secondary.  For what it's worth, every parametric CAD product in existence works the same way.