creating an assembly of components from a multi- body part

[richard_pears]

Hi,

I am experimenting with new modelling methods,

as opposed to modelling each part and assembling via constraints

I have found the create components button that allows me to create an assembly of multipme components from a single multi body part.

So I model an assembly as one part but multi body

then create the assembly and its parts at the end by this feature.

The downfall is that if I have multiple parts that are the same,

I cannot find a way to make it recognise this and instead of creating 4 different parts for it to make just 1 in 4 positions for example.

If anyone knows an efficient way of doing this that would be much appreciated.

I have also seen the create layout tab, but I have not used this before.

Maybe I would be better using this?

I really like how easy it is to create associativity when everything is modelled in one part you don't have to project, copy geometry or share expressions for example, this is all much easier working in just one part. And when you do create the assembly all components are grounded at the origin but automatically in the position they were in the original part. So it saves me using constraints.

The way I am doing it at the moment to solve my problem is to create just 1 of the components if I have several the same. Then pattern or copy it once I get into the final assembly. But it feels like I am doing the same work twice.

Please if someone can help me, or maybe direct me if they have experience, is the create layout function a better way to achieve what I am trying to do, I understand you can make blocks and things in there. I watched some videos on it a while back, but also seems like I'm very close to achieving what I want in the method I am currently using also. Much appreciated if anyone can advise here.

[kacper.suchomski]

Treat the multi-body part as a sketch.
Do not duplicate patterned elements in a multibody part unless it is necessary to create the correct geometry of other elements.

[CCarreiras]

Hi!

I use often Multisolid workflow to achieve the final model, mainly for parametric models.

I create Kind of a "Scheme" model and i insert there all kinds of information i need to the final model: parts, planes, surfaces, references, expressions, parameters, etc, etc.

If the same part will exist several times  in the final model (in the assembly), i only create a unique representation of each part (solid) in the multisolid part.

Sometimes i need to create more then one equal solid, but in the process of turning the multisolid to assembly, i only select one of each kind.

Later in the assembly i add the other copies using patterns, mirrors or adding manually using constrains.

Of course there's some exceptions here and there, but if you continue using multisolid workflow you will get there.
Note that, in every method will be pros and cons...

[kacper.suchomski · Accepted solution]

I will also add that it is not always worth preparing all the geometry in a multi-body file. For example, creating a pattern of holes in a single part (derived from a multibody) can make it much easier to add fasteners at the assembly level using an associative pattern.

But as you study and work, you will learn many good practices and optimal methods.

[Mario.VanWiechen · Accepted solution]

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@kacper.suchomski wrote:

I will also add that it is not always worth preparing all the geometry in a multi-body file. For example, creating a pattern of holes in a single part (derived from a multibody) can make it much easier to add fasteners at the assembly level using an associative pattern.

But as you study and work, you will learn many good practices and optimal methods.

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I typically place my skeleton part in the assembly as a phantom part. I then have all the patterns available to me to place components

[jtylerbc]

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@kacper.suchomski wrote:

Treat the multi-body part as a sketch.
Do not duplicate patterned elements in a multibody part unless it is necessary to create the correct geometry of other elements.

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This has some reasonable logic to it, but I disagree slightly as it is part of my solution to @richard_pears question regarding how to handle duplicate parts.

My method when there are multiple instances of the same part is to create them all in the multibody part, using feature patterns if possible.  However, I only derive the first instance into an individual part file.

At the assembly level, I will then use the geometry from the multibody part (which is always in my assembly) to locate the additional instances.  This typically happens one of two ways:

1. Component Pattern in the assembly, associated to the Feature Pattern in the multibody part.
2. Manually constraining the additional instances, but constraining them to the matching faces from the multibody part instead of to the adjacent parts.

The multibody part ends up with its BOM structure set to Reference, and visibility turned off in any View Representations that are going to be referenced by another assembly or a drawing view.

@richard_pears, I use the "Make Layout" command when I am creating the multibody part, but it is not 100% necessary to do so.  This is really just a shortcut to common settings you might want for such a part.  When you use this command, you get a part that is:

• Grounded at the assembly origin.
• Has a BOM structure set to Phantom by default.

One thing to note with this command is that the Phantom BOM structure may or may not be what you want.  Phantom removes the part from the Parts List, but still includes its mass in the total mass of the assembly.  This is not a problem for layout parts intended for a Frame Generator assembly, since they often contain no solid geometry (planes and sketches instead).  However, for a multisolid layout, the inclusion of the mass can be a problem.

For example, I normally use multibody modeling for designing steel weldments.  Let's say that my layout part contains all of the geometry, and I have at some point set its material to Steel to estimate the weight before I'm at the point of exporting out the individual parts into an assembly.  When I do create the assembly, and put the layout part in it to use as locating geometry, it doubles the weight of the assembly.  You can avoid this two ways:

1. Manually override the layout part's weight to 0.
2. Set the layout part's BOM structure to Reference instead of Phantom.

I have used both methods, but normally use the second.  If I could, I would make the setting default to Reference instead of Phantom.  Reference really has no downside in this application, and I'm not really sure why Phantom was chosen as the default.

[richard_pears]

Thanks Mario,

I didn't think of this, but I like the idea 

because I often like to pattern the body in the multi part model, otherwise I find it hard to complete the design as there is lots of information missing. I already have the multi-body part in my assemblies but never thought that I can use the pattern in the original part to link to when patterning the part also in the final assembly. 

I'm very happy with this as even though I am slightly duplicating some work, at least they should be linked together so if any future modification I only need to do once :).

[richard_pears]

Hi kasper,

for me unfortunately it is very common that as you say - the bodies are needed to complete the geometry of other parts. as I use boolian features between parts etc to make the geometry.

Thankyou for your advice on many of my posts I join this forum only yesterday and am learning a lot! - even in cases where the reply at least confirms my current understanding, at least I also learn I am not missing something.

[richard_pears]

thanks, associative pattern is something I have never really used, but it seems like I am missing out here.

i will explore using this.

am I right in thinking that associative pattern works associative to other patterns.

not sketched for example.

I have found it limiting that in inventor you cannot make a patter associative to a sketch in an assembly level.

but you can do this at a part level it seems.

overall the associativity seems very easy in a single part. but not very good at assembly level - hence why I am leaning towards this multi-body part approach.

I am yet to try it, but I am hoping that I can make a pattern by sketch at part level in my multi-body part. Then make an associative pattern at assembly level that is associative to the pattern in the multi body part to pattern the component in the final assembly. may be at least one solution to duplicate parts in multi body modeling :).

[kacper.suchomski]

An associative pattern and a pattern based on a sketch are 2 different things. You can see the use of the associative pattern in assembly in examples 1 and 3 of this video:

https://youtu.be/3N4-M2QDGbA?feature=shared

[richard_pears]

Thankyou @jtylerbc 

Make layout is something I have not used yet.

I have seen some video demonstrations, I will have a go with it. It seems like the blocking might really help me with the duplicate parts problem, as it will recognise the parts as the same. compared to a standard multi-body part that doesn't recognise this.

thankyou for your insights into BOM structure and weight solutions also, these things I will ned to consider for sure - as we are just moving over to inventor and need to create BOM's so I am also looking at exporting them. Usefull tips, thanks.

[richard_pears]

hi @kacper.suchomski 

yes sorry if I was unclear.

I mean to create a sketch based patter in the multi body part.

then in the assembly maybe I can pattern the component - making the assembly pattern associative to the original sketch based pattern in the multi body. SO this way if I change it in the mulit-body it should update in the assembly.

[jtylerbc]

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@richard_pears wrote:

hi @kacper.suchomski 

yes sorry if I was unclear.

I mean to create a sketch based patter in the multi body part.

then in the assembly maybe I can pattern the component - making the assembly pattern associative to the original sketch based pattern in the multi body. SO this way if I change it in the mulit-body it should update in the assembly.

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Yes, this works.  The associative pattern can't technically follow the part sketch, but it can follow the part's sketch-based pattern.  I use this method often in combination with the techniques I described earlier.  Circular, Rectangular, and Sketch-Based patterns all work with this method.

[Mario.VanWiechen]

Just a note for those who place the multi body part in your assembly, edit the weight to zero or close to it.

Just spent a couple of hours trying to figure out why my COG was skewed off the wrong way. I use a sheet metal template to create my multibody and since it has parts it has weight, more than I would have thought. LOL

[jtylerbc]

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@Mario.VanWiechen wrote:

Just a note for those who place the multi body part in your assembly, edit the weight to zero or close to it.

Just spent a couple of hours trying to figure out why my COG was skewed off the wrong way. I use a sheet metal template to create my multibody and since it has parts it has weight, more than I would have thought. LOL

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Especially true if you ever actually set the material in the multibody to estimate weights.  I mentioned this in an earlier post, but in case you missed it, you can also set the BOM Structure for the multibody part to Reference instead of Phantom.  That will take it out of the physical property calculations as well as the BOM/Parts List.