How to find errors in timeline which pops up after changing a value in parameters.

[tbenkerE2YG2]

I am a 3d hobbyist and I have been using fusion 360 personal version to design things.

When ever i create a  multipart, parametric model I suffer from the same issue. The original version looks and prints great but as soon as i change any value at least one error pops up. When I correct that several others pop up. I can not find which error is where in timeline etc. If I use construction plane, projection planes which is almost needed all the time with multipart things get worse that I prefer to start from the sketch rather than trying to find the errors and correct them.

I know this is because of my poor designing skills and i want to improve. The you tube tutorials i watch taught me how use all the functions, but all in their isolations and not in a big project context. And I feel like the order i need to proceed with designing and the way i link the parts effects the end result.

Can please post a few video links that will explain the followings. I have no budget that i need them to be free as well.

- Workflow for Planning and combining multipart projects

- Things to be careful or avoid when creating parametric models

- How to correct filet/chamfer errors without deselecting and reselecting hundreds of faces, edges, planes.

- How to use timeline efficiently (all the videos I watch explains it like a video player, I would like to know how to find the planes created, features added and errors popped up in the moment of timeline.

- I try my best to create new component for each part and be sure that any sketch, feature etc are contained under them. When i create construction planes, projection planes, god forbid if i copy anything from an other component in to a new one things get messy. I have been using computers for more than 40 years now. It is clear that instead of tutorials trying to explain it like file explorer (which is almost innate to me now) I need to learn in depth of project folder management specific for Fusion 360.

Thanks in advance and cheers.

Thanks in advance. 

[davebYYPCU]

No file, video, or pictures detailing the problems.

parameters that cause failure, 95% of problems will be due to sketches that are not fully constrained.

Might help….

[tbenkerE2YG2]

Thanks for the reply.

I did not attached any file as i do not have any problem with a particular model. This becoming a standard issue whenever i try to design a multipart projects. It is not the model it is me.  I have problem with my design skills and knowledge level. I was asking you to recommend some videos I can watch and learn more and improve my skills. Especially on the subjects i listed in the original post. 

[jeff_strater]

This is a great topic.  A while ago, @Phil.E and I did a class on this topic at Autodesk University:  Debugging Your Fusion Design .  It's a bit dated, but most of the class should be relevant.  It focuses not only on fixing the problems, but also as much on preventing the problems in the first place.

A couple of high-level points:

• if you've ever done any programming, you will be familiar with the idea that one syntax error can cause hundreds of "downstream" compile errors.  Fixing the first one will often remove many of them.  So, when debugging, always look at the first error in the timeline first.
• fully-constrained sketches are your friend.  While it can be a pain to fully constrain a sketch, they do tend to behave better under edits such as parameter changes.
• large parameter changes can cause big jumps in sketch geometry, which can sometimes cause "flipping".  This should not be the case, and if it happens, would be a bug, but sketch solving is hard, so some amount of this will always happen.  If this occurs, and the parameter change is large, try Undo, and then make the same change in increments.  Yeah, it's a hack, but sometimes those are necessary.
• Never delete stuff (particularly sketch geometry) if you do not have to.  Fusion's entire entity tracking scheme is based on the identity of sketch curves.  If you delete one of those, any faces/bodies/etc which depends on that sketch curve will fail.
• Warnings are bad, too.  One of the misunderstandings (and, TBH, one of the design decisions I now regret) is that you can ignore warnings.  While a warning allows compute to continue, there is design intent loss with every warning.  Don't ignore warnings.
• Fix the errors and warnings immediately.  Don't let these things build up, thinking:  I'll just fix them later.
• Test as you go.  This is one lesson I had to learn along the way, and is now probably the most important thing that I do to prevent future errors.  If you identify up-front, which parameters, dimensions, etc are likely to change, then, at every step of the design, just try changing those to values you expect to use.  Even try setting them to values you don't expect to use.  Don't wait until your design is complete.  Even in your first sketch, try changing the parameters with just the sketch visible.  Does the sketch look reasonable to you under these changes?  If not, add more constraints or dimensions, or sometimes even construction geometry, to help the sketch be more stable with these edits.
• choose the "most stable" reference whenever possible.  Almost all timeline errors (I'm tempted to say all errors) result from geometry references.  Whenever you pick geometry in a command, that is a geometry reference, which can be brittle.  But, some references are more stable than others.  If you can pick an origin workplane instead of a body face, that is likely to be more stable.  Or, even, if you can avoid a geometry reference at all, that is even better.  While it is convenient and easy to pick geometry, every one of those is a potential source of a future error.  Instead of projecting an edge into your sketch and dimensioning to it, can you get the same geometry using parameters, or dimensions to the sketch origin?

That's all that comes to mind off the top of my head.

[Phil.E]

Delete should be avoided if possible, try to edit instead of deleting.

If you must delete an object, see if Remove works instead.

Avoid this kind of modeling: creating a big, fully featured body and then splitting it up with split body. Fusion sometimes loses track of which body is "body 1" vs "body 2" when editing prior to a Split Body operation in the timeline. If you are doing this, please provide a model so I can show how to work around the need for split body.

And both of these bits of advice are nearly moot if you try to just live "at the end of the timeline". Going back in time to make edits will necessarily cause the model to compute. If you must go back in time, first seek to make the change you want at the end of time. As I like to tell my students "the end of the timeline is the thing you ship to customers", or in your case "send to the 3D printer". 

[tbenkerE2YG2]

Thank you very much,

These are excellent suggestions. When read, they must be sounding simple and obvious for most of you, They are all "ahh haaa" moments for me. Few of them made me think "How could i missed that" but  when you are a beginner you simply miss. 

I could not figured out how I can manage your "So, when debugging, always look at the first error in the timeline first." comment. As i mentioned, my original model looks perfect, prints flawlessly as well. The error messages start once I change the parameters for a different version. I do not know they were coincidences but the first error messages pop up are usually towards the end of the timeline. After correcting them new ones pop up  for features/ sketches before that point. Your " Test as you go" comment would have solved this but i did not test them.

Another one is "If you can pick an origin workplane instead of a body face, that is likely to be more stable." I understand what you mean but while designing i feel like i have to chose a face, body etc  to be able perfect fit everything. Do you suggest, i should start a new sketch from the origin for each section and then move and align it to part?  

I will definitely watch the course you recommended as a first thing tomorrow morning. Your comments were rather eye opening i can not wait to learn more from that course.

Thank you very much

[TrippyLighting]

My experience with such designs here on the forum is that many users wait way too long to start debugging the design.

Whenever you complete a sketch that uses parameters or features that use parameters, start charging them and see how the design behaves.

Use Modify->  compute-all to ensure the timeline is completely recomputed and possible errors are caught.

If errors pop up in the timeline, find the root cause and fix it immediately. Be sure to move forward only when all errors are fixed.

Overall, this is less work.

[TimelesslyTiredYouth]

With your sketches, before finishing the sketch, ensure that all drawing are black, this ensures that the full design is constrained. i believe this is a good practice to just differentiate the design going from blue to black so in you history if theres an error you can always look back at original sketches and see if any unconstrained blue drawings exist.

[TimelesslyTiredYouth]

This is a pure curiosity question for sake of learning, but is there a setting that automatically does a compute during paramater change, or something to do a compute all for ever edit?

Kind regards 

Ricky

[Phil.E]

Great points. Always test your parameters by changing the values a little to see the result.

Since I brought up teaching, I'll share an image AI helped me create, illustrating the following point. Would you expect an electrician to make all the connections in a home before testing any of it? If it's important enough use a named parameter, the system needs to be tested.

Having learned many hard lessons I try to avoid this situation:

Test early

[jeff_strater]

---

@TimelesslyTiredYouth wrote:

This is a pure curiosity question for sake of learning, but is there a setting that automatically does a compute during paramater change, or something to do a compute all for ever edit?

Kind regards 

Ricky

---

By definition, changing a parameter always does a compute, unless you disable it:

otherwise, changing the parameter would have no effect.  No, there is no way to force a Compute All for every change.  That would be pretty bad, IMO.  The performance impact of that would be undesirable.  Instead, choose points in your design process where things feel stable, then do a Compute All, just to make sure your design is in good shape.  Then, save it.

[jeff_strater]

"Another one is "If you can pick an origin workplane instead of a body face, that is likely to be more stable." I understand what you mean but while designing i feel like i have to chose a face, body etc  to be able perfect fit everything. Do you suggest, i should start a new sketch from the origin for each section and then move and align it to part?  "

Yeah, that specific example is pretty limited.  It was meant to be more general.  Choose references that are more stable whenever you can.  Sometimes, by design, a model face will be coincident with an origin workplane.  Say, you drew a cube on the XY plane, and you wanted a second sketch on the face of the cube that coincides with XY.  You can pick the cube face, or you can again pick XY.  XY will always be more stable.  Second, if the opposite face of the cube is 20mm from XY, and you want to sketch there, you can sketch on that face directly, or you can define a parameter that is 20mm, and create an offset plane from XY using that parameter instead.  Same plane.  If you use your parameter, also, to define the cube extrude distance, then everything will update as you expect.

Of course, this can get out of hand, and at some point, it is just too complex to do, and too simple to just sketch on a face.  But, being aware of the "more stable vs less stable" difference is something to keep in the back of your mind, if you plan to do a lot of editing.

[tbenkerE2YG2]

Thanks to every one of you for your replies.

I think i have an other mistake that makes things harder. Drawing so many construction lines. As i am not an engineer or designer and have difficulty seeing the screen, I feel safer to draw construction lines to ensure i am at the right coordinates. This makes debugging even harder.  I am trying to minimize it but i need to avoid them all if they are not absolutely needed.

[davebYYPCU]

If you have that habit of making construction lines assisting with shape, I recommend you keep doing that, but more likely to cause trouble is overlapping duplicate lines (lines on top of lines).  Those would annoy the sketch solver more.

Make simple sketches and fully define as you go.

Might help...

[tbenkerE2YG2]

Those overlaps are indeed very annoying.

Even before I start a new design, I have a clear vision, how it should end up, what components it should have and the dimensions of the crucial parts of the design. So I usually try to create formulas needed to achieve that design put them in parameter before drawing the first sketch, but i can not create any formula for a part that i will have to add later. (With 3D prints, parts might not be as strong as you hope and you realize it once your prototype breaks. So you create additional support parts).

Probably because of the frustration, I do not define formulas for these new parts. It seems tedious at that moment. Now i am learning the hard way that correcting them is much more tedious.

[davebYYPCU]

Attach a demo file, with the problems, - you are able to confirm my guesses as to the problems, 

it should be a simple matter of changing a wall thickness for example, and the file does not break.

Duplicated overlapping lines, and not fully defined sketches are obvious from your descriptions.

File > Export > to your hard drive, then attach to a new message.

Might help...

[tbenkerE2YG2]

I watched the video you recommended and learn a lot. I think i am bookshelf type 2 designer. Now I need to improve my sketch skills to become type 1.🙈

[tbenkerE2YG2]

Dear  davebYYPCU,

Thanks for the offer. As i mentioned before it is not direct problem of any of my models. It will be waste of your time or anyone who will look  at them. With every design I learn new things and start to not repeat my mistakes. With every new design, I experiment with new things and make newer mistakes. Even the comments in this post helped me realize many mistakes I made. At the moment I am at "Do not give the man a fish, teach him how to fish" stage. I also realized that , somehow skipped the "Self-paced learning for Fusion". Now i am going back to it and try to improve myself.

[TrippyLighting]

Please don't use the reply section at the bottom of a thread, as it always looks like you are replying to yourself.

If you want to reply to a specific post, please use the reply button in that post.

That makes it easier to follow and provide help.

[TimelesslyTiredYouth]

I've been wondering, why does replying yourself exist? if you forgot to say something just add another reply to the same comment so they still get the notification...