Fundamental misunderstanding? Components seem to move unexpectedly to incorrect (older?) positions...

[jgordis]

This is, I'm sure, a newbie question. I am not understanding components seem to end up in positions other than where I put them. I'm assuming this has something to do with sketches used earlier in the timeline? 

Perhaps I'm missing the relationships between sketches, bodies/components, and the timeline?

I seem to be repeatedly putting a component back in its correct position, even if I've created a rigid group.

I appreciate any insight I can get here...

[g-andresen]

Hi,

Please share the file for reply.

File > export > save as f3d on local drive  > attach  to  post

günther

[jgordis]

Attached (please let me know if this doesn't work). Thank you for the help...

[jgordis]

I shared the F360 file above... thanks...

[laughingcreek]

so I would say there may be a few concepts yo don't have down yet.

a few rules of thumb-

-fix yellow and red errors in your timeline AS THEY OCCUR.  let them hang out there is asking for trouble and can cause all sorts of difficulties.

-position components relative to each other with a joint.  or by creating them in place.  don't "move" or "align" them.

-move is used to position a body within it's component, not relative to another component.  it has it's uses, but this isn't one of them.

-a deign like this shouldn't have any move, align, or position captures in the timeline.

[jgordis]

Thanks very much. A follow-up question, if I may: I create a component using a sketch, and I've been "moving" the component into its position, and the sketch is left behind, so to say. The sketch was not moved with the body it generated. So according to your second bulleted point, if I don't create components in place, I can reposition one or both components using joints. Do the associated generating sketches then stay with a component that moved? Or are sketches used and then become 'outdated,' and can be deleted?  I appreciate the help.

[Drewpan]

Hi,

The Gurus have left you some excellent advice below.

I would suggest that your components are moving for a couple of reasons. Firstly you may be creating them

and then moving them to where you want them. If you fail to "Capture New Position" then they will snap back

to the original position. The other issue is that you are probably moving them into position but not using

Joints to keep them there. There is a thing called a Rigid Joint for joining components statically. If you use a

Joint then they shouldn't move unless it is a moveable joint like a Revolute or Slider Joint.

One common method I have seen in this Forum is to create components in one of two ways. You can create them

in an isolated way using the Origin for all of your Sketches and create and model them THEN use a joint to put

them where you want them. The other method is to build them IN PLACE where you want them. Using this method

they will not move around. I have used both but my personal preference is that if it needs to be in a specific place

then put it there with a joint.

In support of the Gurus - if you get a yellow or red error on the Timeline then FIX IT AS YOU GO. If you don't then

your model will probably (often certainly) fail if you try to make it or 3D print it. It is a bit like building a bridge

and you know there is a problem but it falls down before you can go back and fix it. If you had fixed it as soon

as you realised there was a problem, it will not fall down. You need a firm foundation when you model, the timeline

is your foundation.

Cheers

Andrew

[laughingcreek · Accepted solution]

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@jgordis wrote:

... I create a component using a sketch, and I've been "moving" the component into its position, and the sketch is left behind...

2 main things will cause this.

1-the sketch wasn't in the component.  so it doesn't move with the component when it's  moved.

2-if the the sketch is in the component, you aren't moving the component, your moving the body around within the component.  the component itself is staying still, so everything else inside the component also stays still (other things that are in the component are: the component origin (deferent from the model origin), sketches, construction geometries (construction planes etc.), other bodies you may have created, other subcomponents you may have put in it.)

...Do the associated generating sketches then stay with a component that moved? Or are sketches used and then become 'outdated,' and can be deleted?....

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if you are doing things correctly, the bodies won't be moved away from the sketch.

sketches do not become out dated.  never delete a sketch that was used to create geometry, you will create an error in your timeline (DO delete extraneous ones that are unused or created by accident. keep things tidy).  you will go back to this sketch to make edits to the model.

also you will (almost) never need/want to use position capture.  keep them out of your timeline.

[jgordis]

Thanks very much for the help. So, if I use joints and one or both of the components are moved into position to establish the joint, since the component is moving, everything contained within the component moves together (bodies, sketches, etc)?

[jgordis]

Again, many thanks. I've been avoiding using joints because I really havent fully understood how to use them. For example, how do you position one component between two other components, symmetrically but not contiguously?

[Drewpan]

Hi,

Joints sound scary until you work out how they work - then they ARE scary (not really).

I would strongly recommend doing the tutorials in the Fusion Documentation, especially the ones about

Joints, but you will find all of them will help. Then do the AutoDesk Self Paced Learning video tutorials. I

actually worked out joints by watching the @TheCADWhisperer on YouTube (he is a Guru here too). He has

a really good series about modelling a car jack that explains Sketching, Extruding, Cutting and Shaping, and

then putting it all together with joints. The method of getting the jack to work as you turn the handle is really

cool using joints and motion links. It is well worth watching and learning.

Cheers

Andrew

[TheCADWhisperer]

@jgordis 

I recommend that you start over from scratch.

Post your new attempt here after each and every sketch/feature for diagnosis by the experts here.

Your previous attempt is a house of cards built on a foundation of quicksand.

I usually make at least 2 attempts and often three or four before I have a robust foundation that will not break on editing (within logical reasoning).  Never ignore unresolved issues highlighted in the Timeline in Yellow or Red.  Fully define all of your sketches.  No need to repeat sketch geometry.

[laughingcreek]

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@jgordis wrote:

... how do you position one component between two other components, symmetrically but not contiguously?

---

depends on design intent, but one way is to have a sketch at the top level (usually referred to as a skeleton sketch) the defines the join points.  then you just hang the components on these points with joints.

or you can have that sketch in a component, which can allow for things to be more dynamic. (the sketch will move around with the component, but keep components jointed to it positioned to it relative to the component, instead of being static in the model)

or you can place a joint origin, which can be at the top level or in a component.

or when you define a joint, you can offset the joint position from within the joint dialog box.

my suggestion is to just start using them.  they get easier once you get past the initial novelty. 

[evanp4509U4JZ]

It sounds like the way you are creating components might be the root of the problem. You said you make a sketch, make a body from that, then convert to a component. This leaves the original sketch in a different component and makes things jump around during some edits. I believe the better way is to first choose "New Component" from the "create" menu in the upper left. This will create a new component, as a child of whatever component is active or chosen in the create process. This way the sketch that creates a body within that component is within that component and edits should be smoother.

[jgordis]

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Thanks very much for your help and suggestions...

[jgordis]

So you can have a sketch not associated with any particular body/component, and then create joints between points in this sketch and joint origins installed in other components... Thats very interesting - thank you.

[jgordis]

thanks very much...