Workflow for furniture assembling

[fiew31]

Hello,

at the moment, i really stuck with a solid workflow for building furnitures. In my case i want to design a sofa that consists of multiple parts like the middle seat and two identical (but mirrored) outer seats. 

To keep it simple first, all the bodies are basically cuboids consisting of 6 panels each (like in real world) that are mounted together, but here i do really stuck, since i want to make these parametric in their dimensions to easily adapt it later.

For this i added user params like:

material_thickness_standard=15mm

seat_left_width=1200mm

seat_left_height=600mm

seat_left_length=700mm

..

In my sketches i use these params accordingly.

First question:

Is there a way to "automatically" compute the dimension that results from the spacing between two other components/panels position? Can we make it dependent from other components position? I know we can have linked projections, but is this advisable or will this end up in a mess?

At the moment i calculate the dimensions with formulas like seat_left_width - 2 * material_thickness_standard but i am afraid this will become much more complex in future designs with further components to consider like seat_left_width - 2 * material_thickness_standard - other_component_height / 2 + whatever * 4

Second question:

How would you assemble these single parts so that there is a solid but flexible result?

My first attempt was creating every component independent from each other (no sketches on top of other components, only use the coordinate planes) an then moving all 6 components(panels) to there desired places and making a rigid group from them. This results in chaos when i change for example the width, since it seems the position of the panels wont follow any size changes to other components in that rigid group. So in the end, there is a unwanted gap somewhere.

The same applies to as-built joins. I think as-built joints are the same as rigid groups in that case but only between two components instead of multiple.

But connecting every part with every adjacent part using usual "Joints" will do somehow what i need but feels really laborious and also comes with other problems like that i end up in creating a joint loop, where the last panel  cant be connected to the first one (fusion complains about it since its already joint to another part).

I feel like some basic understanding of assembling stuff is missing, since i think that connecting 6 panels shouldn't be that hard at all

Do you have a workflow/tipps for me?

Thanks!

[davebYYPCU]

Build the centre component - centred on the File Origin.

Build the outers using symmetry on their own origin.

Join the outers to the sides of the centre panels.

Do not use as built Joints if changing parameters.

Might help…

[Drewpan]

Hi,

You could use Configurations to help organise your number of designs. If you are going to use Parameters then make

sure you have a small number of them for each critical part and base all of your calculations off combinations of

them. The more you have then the amount of complexity will expand rapidly.

There is a way to automagically calculate spacings and such, but it will involve another parameter. This is one of the

reasons you must minimise the total number to reduce the complexity. An example might be.

Sofa_Length = Mid_Length + ((Outrigger_Length + Spacer) * 2)

But you might have "arms" on your sofa so you might need.

Total_Sofa_Length = Sofa_Length + (Arm_Length * 2)

If you have no "arms" on this design then Arm_Length = 0, so Total_Sofa_Length = Sofa_Length

However you do it, minimise the number of parameters and always relate them back to each other so that by

changing only a small number of parameters gives you the new design.

In terms of workflow there are two basic methods - Design at Origin and Design in Place. Either will work well on

their own or in combination. The trick is knowing when to use each one and it is not always obvious.

Designing at the Origin has benefits and keeps things simple and then use a Joint to join it up to something. Design

in Place allows you to use a relative Origin but can involve more work creating planes and various geometries to

make it all work. Not always a bad thing. Then use As-Built Joints.

I tend to split my designs up into assemblies and sub assemblies as I would build the finished design. You do not

have to use Rigid Groups and I would avoid them if you are going to be changing parameters often. What you can

do instead is use simple joints within sub-assemblies, and then join those sub-assemblies to other components

or assemblies. I am currently designing an 18th Century Naval Cannon and this is an example of what I have done.

I design things either as I need them or because I have to in order to continue later. When designing the Rear Axle

I first need my Rear Axletree which has round ends for the wheels. Next I need the Ferrule that goes around the

end of the rounded ends for the wheel to spin on. Now comes the actual wheel Truck. But the Truck is a

sub-assembly of four identical semicircular parts that are riveted together. I have created them and used three rigid

joints - top and bottom inner and outer. The rivets are a nightmare but I have also created Rigid Joints for these.

Since I have created my joints within a sub-assembly, I can create a simple Revolute joint between the Truck and

the Axletree. I finish off with a Linchpin through the Ferrule and the Axletree to hold the Truck on but I only need

a single Rigid joint as all other joins will keep everything in place. Mirror the Axletree and apply the joints to the

new Components. Now I can use a single joint between the Rear Axle and the rest of the Carriage.

By doing it this way my workflow has basically built itself. I have only used joints where I need to. If I change say

the diameter of the Truck then I move the timeline back, make the change and fix any breakages when I move the

timeline forward.

The biggest thing about workflow is to try and keep as much together as possible, work in a logical way, name stuff

so you don't lose track. Also keep track of which is the Active Component. The last advice I would give you is to take

the role of a junior designer on a team of designers and your part will have to fit with another teams part. If you

design like this you will be more logical in the way you set things out as you KNOW others will have to decipher your

work in the future. Many an engineer and designer has said to me that they designed it that way for some reason

and that they "would remember" some months down the track - most didn't. A good design is easy to follow as well

as being innovative and functional.

Cheers

Andrew

[fiew31]

@DrewpanThanks for your extensive advices, i'll keep then in mind for my next project! 🙂 

I think the hardest part is, that i know that there are tons of ways to do it but i personally tend to overthink solutions which often ends up in some kind of numbness without moving forward and beeing frustrated about doing not the "optimum" ... and i also think one hard thing is to find a way to speed up things and get comfortable with all the stuff. For example creating everything at the document origin first makes it very hard to select desired points for joints etc., since they are all overlapping and hide/unhide any other component everytime is very laborious ... i have to find a way to make this with more ease^^

[davebYYPCU]

Fix the clutter, with eyeballs.

Might help….

[Drewpan]

Hi,

If you find Design at Origin is not working for you then Design in Place will be the better workflow. As mentioned, it

involves you creating more of the support geometry and tools like planes but there is less moving things around.

When designing there are many ways to do the same thing, the way you do stuff does not matter if you get the right

end result. Sure you might do it the hard way, I do frequently, but you can always look for alternative ways and this

makes you a better designer as you learn these techniques. And practice definitely makes perfect.

When you are designing, use the browser tree visibility option and only have what you need visible, it will help you

concentrate on the job at hand without all the clutter. You may find that in a simpler work environment that suddenly

Design in Place works better.

Using Components, Assemblies and Sub-assemblies will really help with organisation and keeping things logical.

Designing things is all about solving problems and being logical. It will come with time so stick with it. If you are

struggling then take a break and model something else for pleasure and practice. Downloading someone else's

Engineering Drawing and modelling that is a good way to practice. The hard work is done and you learn the model

techniques by doing it. I quite like steam engines and have done this for ages.

Cheers

Andrew

[fiew31]

---

@fiew31 wrote:

But connecting every part with every adjacent part using usual "Joints" will do somehow what i need but feels really laborious and also comes with other problems like that i end up in creating a joint loop, where the last panel  cant be connected to the first one (fusion complains about it since its already joint to another part).

---

Sorry, but i feel really dumb about this ...i cant figure out, how to use a normal joint to connect 4 components together, were the last piece again connects to the first component like a simple frame with 4 bars will do ...

I connect Comp2 to Comp1, Comp3 to Comp2, Comp4 to Comp3 and Comp4 to Comp1 ... Fusion tells me for the last joint, that i rigidly connect everything which will not work ... but in real life, i would exactly do this and the two points that will be connected are exact in the same place ...

And any tutorial tells to easily use rigid groups or as-built joins for connecting something like this, because its easier ... yeah ... but its not working parametrical ...

What do i miss?

[Drewpan]

Hi,

Your problem here is you are mixing up modelling reality and Real Life. Remember that fusion is like any other

computer software in that it will round things off. You might not care what a number is to a dozen decimal places

but fusion will. These tiny rounding errors mean that sometimes fusion thinks something will not work when you

and I know that in reality it will be fine. It is one of the reasons that Combining two Surfaces fails so often when

we model them adjacent but fusion thinks that they are separate and not joinable. Thicken one of those surfaces

by a fraction of a mm and Bingo - it works.

Also there are things that we do that are simply not necessary when modelling. If I want a Component joined to

another Component that is fine. If I build a structure that will naturally join up to another Component then I don't

need to model a joint there even though I will join it in reality.

Take a simple square box. I model all four sides as normal. I join the first two sides and then I have a choice, I can

join another side to that or I can join the other two sides. It doesn't matter which way I join them, it will happen

that when I have assembled my box, I don't need the final joint because it is already in the correct place. Now WE

know that you NEED that final joint to maintain structural integrity but to just LOOK at the model it is unnecessary.

It is a different story if I am going to use my model for a Finite Element Analysis - then I NEED that last joint so I

will apply it and if fusion fails I will have to work out how to make it work. These work around tricks are frustrating

to all but necessary sometimes.

Circular joint combinations should work if you have designed them properly but only use them if you need to. If I

have plate held down with four bolts then I will only make ONE joint for modelling purposes but in Reality I will

use four bolts.

Cheers

Andrew

[davebYYPCU]

Four joints, four components.  Should work, because you should not be making a second joint in any corner.

You will get the last joint error if you are misaligning, something in the chain.

Might help….

[fiew31]

So, i tried today with a simple 4-bar frame example where i get the error below when connecting the last joint, BUT this time i could accept and fusion did it anyway ...

So am I correct that Fusion only wants me to warn, that there is no motion possible for this 4 components in this "loop", since they are all connected together? If this is the case, is there anything else that will cause headache later?

[g-andresen]

Hi,

This arrangement only requires 3 joints.

günther

[davebYYPCU]

Can’t see your timeline. Change the length of one bar, do they all change, or does the model break?

Might help….

[TrippyLighting]

Please share that model. We can work from there.

In my experience, there are certainly better and worse workflows, but no workflow fits all situations. One has to always make compromises.

It will take some experimentation to determine what works best for a specific project. With experience, you'll be able to decide upfront which approach is best.