Designing Instruments with Fusion, Joints? Planes? Points? Parametric?

[joe.lacour]

Often when designing I need to place two assemblies at a know position relative to each other and design the best structure between them.  An example would be an instrument where there is a lens and a sensor which have to be at a relative distance, both linear and offset to the side.  The light will go in the lens, bounce off some mirrors and into the detector.  The lens / detector relationship is known and fixed.  The structure between them has to be designed.

So I model the lens and cell, each part a separate file, and stick them in an assembly.  Same with the detector and its associated mounting.  In the main assembly I insert the lens assembly and anchor it to the origin, which is where I want it.  Now comes the detector, I insert it into the main assembly and now I need to locate it the correct distance away in X and offset in Y.   In old CAD I would offset some planes and constrain to these planes so I could tweak the distance if something changes.

What would be the best way to position these two sub-assemblies in the main assembly?

Before you ask, I no longer use multiple components in a file.  For me, Fusion is much faster and easier to use when each part is a separate file and linked to a sub or main assembly.

[joe.lacour]

Here is a screen image

[davebYYPCU]

At the time you Insert the second file, you are given the Move triad, in the Dialogue Box, Set the position values.  If you don’t use this opportunity, ( first and only live once) then you would need Joints.  Design Dependant.

Ground / Rigid Group that set of components, to fix them in place.

Might help....

[g-andresen]

Hi,

In Fusion you can define distances using  joints with an offset.
Supporting are mostly also the use of joint origins, which are set before the assignment of the assemblies.

If you upload a sample file, it could be used to give hints on possible solutions.

günther

[joe.lacour]

Yes, I have that figured out, but it would be really nice to have it joined to three planes, like in SW or similar), to if I need to tweak the position later it can be done.

[davebYYPCU]

This is not SW.  

Why can’t you tweak it later?  Joints are editable.

[g-andresen]

Hi,

In fusion, assemblies (components) are "connected" directly via rigid or motion joints and not via planes.

Günther

[jhackney1972]

Here is a Screencast illustrating what both @g-andresen and @davebYYPCU are saying.  Editing a Joint between your components is the quickest and easiest method of changing the position and holding your components in place.

[joe.lacour]

Yes, I have done that before with components, but I 'm having trouble with doing it to sub assemblies in a main assembly.  Just the part I select out of the sub-assembly moves and not the entire sub-assembly.  Where should the joint be selected?

[jhackney1972]

Please attach YOUR assembly so the Forum users can show you exactly what you need.  If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section of a forum post to attach it.

[joe.lacour]

Here is the assembly, the subs are in the approximate position.  Thanks for all the help.

[jhackney1972]

Sorry, I open the wrong assembly.

[jhackney1972]

I apologize, the top level assembly was not at the top of the list.  That a look at the Screencast for your answer.  I am returning the assembly you sent that I modified but I left it as a F3Z file.  If you do not know how to place it back in your folder, without confusing it with your other original files, I would not open it, just follow the Screencast and edit your original.

[joe.lacour]

John, that really helped.  I didn't know about the grounding.  But when you put the joint for the lens to the cell, you did that in the main assembly.  Would that have been better put in the sub-assembly so it could be change when just the sub assembly was opened?

[jhackney1972]

You are correct, so I did that in another Screencast, it is attached.  In my haste to give you the answer to your sub-assembly question I did not study your model, after all it is yours and not mine.  I hope you now understand how the sub-assembly component seemingly separated from the sub-assembly during the Joint placement operation but re-joins after you say OK.  You did not acknowledge that you understood that from the first Screencast.

[joe.lacour]

John, it looks like I had two pieces grounded, the lens and the cell with no joint.  Ugh.

[joe.lacour]

Yes, I did understand and it has worked fine.  Seeing someone work sure does help.  

Just to discuss, is it common and a good idea to use one discrete part per file and link them into appropriate sub and main assemblies?  It seems like it works better that way and easier to keep track of.  It would be nice if there was a way to see all the structure of the main, subs, and parts in one view.  is there a way?

Thanks so much.

[davebYYPCU]

Activate top level component - file name - and all of the file is visibly displayed depending on the status of the eyeball.

I see advantages of one part per file, but don't use it,

(because until recently you could not edit a linked file in the main design, now there is edit in place and a hierarchy night mare.)

I have one component per part, in the project file, and use eyeballs.

Might help.

[jhackney1972]

@davebYYPCU presented some good points.  Linked individual components and sub-assemblies have a great advantage if the they need to be used in different top-level assemblies.  This makes it easy to model once and use it over and over with the ability to edit the original, either from inside the assembly or out, and then all the linked occurrences will update automatically.  As far as structure, the Browser is your friend, keep it organized and model using proper methods to keep all sketches and bodies under the component which they belong to.  If you are using linked components only, this is automatic, if not you really need to pay attention to it.

Good luck with your Fusion 360 modeling and come back to the Forum when you have questions.  Post your model a little earlier next time to get a quicker and more relevant answer.

[joe.lacour]

Thanks John and Dave.  These screen videos you posted are very informative.  Thanks.

Yes, if you don't watch it, you can end up with sketches, joints, etc in the top level and not in the linked components.  That has happened to me many times and sometimes they can't be moved to the correct location and must be re-created.

I have talked with others that have difficulties and uncertainties in modeling designs with many parts and sub-assemblies such as I have discussed here.  If you have a screen video example of a proper main assembly with sub-assemblies made of discrete components, that would be very helpful to me and others.

Thanks so much.  Joe