Why I need more than one sketch?

[matcons24]

I don't understand the concept. For example, take the first lesson (but works also with the second as well) of the PDF I've attached. It's the Autodesk sketch tutorial. Why do I need to do all that number of sketch? Why not using one, make the "double circle", all the 6 hole and the fees arcs in one single sketch? Is also more simple to edit and modify later, it is all in a single file.

Sorry for the (probably) stupid question and thank for any answer.

[Brady_Fulton]

Yes, you are correct, you could do it in one sketch. But then you wouldn't be following directions 😉

Once you've got the hang of the software it is a personal choice, but I do find it quicker to make edits when the sketch is right before the modifying feature as opposed to looking 4 or more steps back to find the sketch that has all the info.

[matcons24]

Sorry, but I didn't understand what you prefer, one sketch with all or multiple ones? And Why?

Also, I still don't understand what are the advantages of making multiple sketches...

Thanks!

[davebYYPCU]

Put it another way, the bigger the sketch the harder to find the reasons the sketch has broken, 

the bigger the sketch, the slower Fusion goes.

The bigger the sketch, everything is being related to everything, Fusion does automatic constraint, and if the constraint isn't the one you want, you start to fix, and surely complicate the process,

For beginners, one sketch per feature, is sort of tidy,

For experts - no need to take any notice of this....

[Brady_Fulton]

I don't have a preference necessarily.

I try to avoid putting too much info on any one sketch.

It's a good habit to:

1. sketch the info needed for your next feature
2. then do the feature
3. then create your next sketch for the following feature
4. etc.

The advantage is realized when you try to adjust a sketch entity that modifies a feature. If that is right before the feature in the timeline, easy.

If the sketch is a dozen steps prior in the timeline, it might take some time to hunt it down.

[TrippyLighting]

You probably should be reviewing Fusion 360's R.U.L.E #1. This will help in planning the reason why sometimes it's advisable to break one larger sketch into multiple smaller sketches.

How mean sketches you are using does not only have to do with efficiency but also how well it conveys design intent.

[matcons24]

davebYYPCU:

Thanks, I understand it a bit better.

I just don't understand what this means for the expert (the last line of your post).

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Fabricator:

Thanks for the answer.

I don't understand what you mean by sketching the info of a new feature and then do the feature. And what are a feature and a sketch entity?

Also, the timeline is global so I don't understand the last line about the advantage of splitting in more sketch for a better timeline.

TrippyLighting:

Thanks, I read it. But the rule is about creating a component and why it is useful or not?

I just want to ask sorry for my bad knowledge of English and the specific Fusion word (such as feature, component, entity, bodies...)

Thanks!

[TrippyLighting]

If you create sketch an then create several components from the same sketch and export the component to be used in another design, it might not contain the sketch and you'll loos the parametric design history.

It depends on what you are doing whether that makes sense or not .

[matcons24]

So what is the solution? In a single file that have more than one component how can I put the sketch to all?

[TrippyLighting]

You make separate sketches for each component 😉

Again, the is not necessary in every case. I sometimes also create more than one component from the same sketch.

[matcons24]

Many thanks! I will keep in mind.

But my question is why I need more than one sketch for a single body in a single component.

[TrippyLighting]

There is no inherent need. I personally like to keep sketches simple.

[Phil.E]

@matcons24

Welcome to the Fusion 360 community. Thanks for asking the question.

This diagram shows why you might need more than one sketch.

Explanation:

Step 1: In this step the basic shape of the part is sketched, and then extruded.

Step 2: In order to make the hole on the top surface, you need a new sketch.

Please let me know if this helps, or if you have more questions.

Regards,

[kb9ydn]

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@matcons24 wrote:

I don't understand the concept. For example, take the first lesson (but works also with the second as well) of the PDF I've attached. It's the Autodesk sketch tutorial. Why do I need to do all that number of sketch? Why not using one, make the "double circle", all the 6 hole and the fees arcs in one single sketch? Is also more simple to edit and modify later, it is all in a single file.

Sorry for the (probably) stupid question and thank for any answer.

---

The biggest reason to use multiple sketches has to do with complexity.  For very complex parts (meaning parts that have a lot of features), trying to put everything into one sketch can make for a very "busy" sketch that is hard to edit because there are so many dimensions and constraints.  It's just hard to see what is going on.  This is especially true when you run into a problem with a sketch and have to figure out where the problem is.  The part in that example is fairly simple so doing it all in one sketch wouldn't be a big deal.

There is also the issue of performance.  Fusion in particular tends to slow down a lot when sketches are too complex.

And to some extent it just comes down to personal preference.  I prefer to use multiple simple sketches as opposed to fewer more complex sketches, but there are times when I find it easier to put everything in a single sketch.  This is one of those things that's hard to explain and you can really only learn through experience.

C|

[matcons24]

Thanks a lot. I finally understand why more sketch helps to keep a clear history!

kb9ydn:

Thanks, very clear!