multibody sheet metal

[MJuric]

I’m answering this from the standpoint of using multi-bodied parts for weldments. I’m not sure why you would use it for parts that are essentially assemblies.

This is exactly the method I’d avoid. You can’t reuse any parts (without splitting them out),

If you have parts that you want to “Re-Use” or use often you can make templates of them and insert them.

you can’t use library parts (without inserting them),

How are you getting library parts into assemblies etc without inserting them? Maybe I’m not understanding this one.

configurations won’t work they way they are intended,

Don’t understand this one either. Configurations in weldments work the same way they do everywhere else.

drawings are harder,

Not sure why. What is harder about making drawings from a multi bodied part versus an assembly or anything else?

file management is impossible,

Don’t understand this at all. You have one part.

mistakes are much easier to create, errors are harder to troubleshoot

Again, not sure why that would be. Everything is in one file. Errors are easily seen and rectified.

motion is shot. You’re just avoiding an assembly, but limiting everything else and causing so much more work. You don’t like your nose, so cut it off and bleed to death.

While you could do motion using multiple configurations, I’m really not sure why someone would use multi-body for an assembly…I mean it’s an assembly not a multi-bodoed part.

For sheet metal, I can see using multibodies for really simple (one or two bend parts), within a weldment, but not for other stuff. It’s not any more work to use one part per file.

I don’t really agree with this statement. You have a single part that is treated as a single part. Modeling it as a single part is easier from start to finish from modeling thru ERP thru manufacturing.

When I create a weldment all the properties are propagated via the weldment insertion. That keeps me from having to fill in nearly any custom properties which I would have to do individually for each part. I don’t have to mate them. If I want to I can create multiple parts from a single sketch. This is extremely helpful for weldments that have many individual parts that run thru an entire cross section. See the pic below. One sketch, two extrudes and I have an entire base, done. All the parts have many of the custom properties we use automatically populated.

All the changes for the entire cross section are contained inside a single sketch. Change the sketch, everything else updates. No opening multiple parts, hunting down which mate locates the part etc.
image.png

and I’m convinced it keeps the software from crashing as much. It’s like using a swiss army knife to build a house - it can do some of the work, but it sucks at most of it.

When I have written best practices for companies, replacing normal assemblies with multibody parts is definitely on the “avoid it” list.

I’m convinced that the reason for so many crashes and other discontent with SW is that people are forcing the software to work the way they want it to work, rather than just learning the way it actually does work. There are times to step out of line, but I see this as an unforced error.

The vast majority of SW crashes I have happen in assemblies. In my opinion this is probably because of mates, rebuilds etc. Non of that exists in a multi-body part and I can honestly say I can’t remember but a few occasions on some really funky weldments where I’ve had SW crash in a weldment.

As to replacing assemblies with multi-bodies, I agree, that doesn’t make sense to me but if you’re making a weldment using multi-bodied parts is, at least IMO, significantly superior to assemblies.

[matt]

We avoid them as much as possible but there are instances where I believe that it’s much easier to have it as a multi-body part then as an assembly with individual parts. Of course, that way of thinking might come from the fact that I started off that way before learning about the master sketch method, but I still think that way for instances.

We use multibodies when we make the beams for our trailers, because they need to follow a specific shape. The same feat could be accomplished with an assembly, but it would most likely be more hassle. Depending on the length of the beams, we might need to add or remove joints for the beam and when that does happen, it is much easier to do it from a multi-body then it is to do it from an assembly. I added a picture to perhaps clarify what I was refering to “beam joints”

image.png

Yeah, I use multibodies for almost every project. Generally I make an overall shape that gets broken into multiple pieces, and it’s very difficult to make nice shapes that are actually separate parts. And sometimes I use other parts for reference. But I never make multibodies just to avoid assemblies. Sometimes even things like captive screws, or pre-assembled purchased parts I’ll do as multibodies.

[matt]

This to me doesn’t look like a weldment. It looks like an assembly of machined and purchased parts with features in folders.

[Damo]

The vast majority of SW crashes I have happen in assemblies. In my opinion this is probably because of mates, rebuilds etc. Non of that exists in a multi-body part and I can honestly say I can’t remember but a few occasions on some really funky weldments where I’ve had SW crash in a weldment.

As to replacing assemblies with multi-bodies, I agree, that doesn’t make sense to me but if you’re making a weldment using multi-bodied parts is, at least IMO, significantly superior to assemblies.

I feel I must agree with you on this one.
Most of the errors I get are from mates flipping, or suddenly thinking they are now over-defined, (where they were not previously, and most often I will simply delete them and recreate the same again and all is good..), or just plain breaking anyway. And sketch references losing there references across parts within assemblies. etc.. I can confidently work with some fairly large MB Parts (200-300 bodies) and run smoothly without crashing.

[Damo]

I really don’t know how everyone else is doing this but we have templates for everything we do if it’s going to flame, lasered or water jetted. To get a flat pattern for a sheetmetal part in a weldment all you need to do is create a view, select body and plop it on the drawing. If you need a DXF of it you just export the drawing.

So, Export the DRW File as DXF..?! Scaled as 1 : 1 ..? That works..?
Many plates we cut would not fit on any size of paper for drawings sheet size..
Or am I missing something here..?

[Damo]

But I never make multibodies just to avoid assemblies.

This is sensible.. And neither would I. Assemblies definitely have their advantages..
And likewise, I would never create an assembly of single body parts just to avoid multibodies. Especially when multibody parts work soooo well.
And with a good cutlist template… Beautifully easy..

Your primary query being about sheetmetal multi-bodies applies too.. If I’m designing something that uses several, or many, folded plates all welded into one rigid form.. It’ll be a mult-body part.. Everytime..

Yeah, I use multibodies for almost every project. Generally I make an overall shape that gets broken into multiple pieces, and it’s very difficult to make nice shapes that are actually separate parts. And sometimes I use other parts for reference.

When you say, “that gets broken into multiple pieces” … Do you mean “Save Bodies”..?
(I’ve seen someone do this and then take these saved bodies and “Convert to Sheetmetal” all over again..
That seemed odd to me, just to have separate bodies for individual drawings.)
There are many thing about this methodology I do not understand..

[Lapuo]

You can do the same thing with the a multi-bodied part.

That is what i said … right??
I completely agree with your response to matt , and as i said i am far more efficient with multi-bodied parts than asssemblies.
My english sucks , so i believe i am getting misunderstood by others.

[mike_miller]

[SPerman]

So, Export the DRW File as DXF..?! Scaled as 1 : 1 ..? That works..?
Many plates we cut would not fit on any size of paper for drawings sheet size..
Or am I missing something here..?

Yes, that works. I usually double check that the view is actually 1:1. Sometimes SW will change that when creating the view.

Are there limitations on the drawing sheet size? I guess if you are buying your sheet goods on a roll, this could be a problem. Otherwise I doubt you need a dxf larger than what SW can create. It had no problem with me setting my sheet size to 1000 in x 1000 in.

[MJuric]

So, Export the DRW File as DXF..?! Scaled as 1 : 1 ..? That works..?
Many plates we cut would not fit on any size of paper for drawings sheet size..
Or am I missing something here..?

Yes, there is a setting in options, see below, that exports DXF’s to a 1:1. You can then just import the geometry into whatever software you’re using to cut the template. In some cases, depending on software, you may have to delete the border etc from the DXF or have it on a different layer you just turn off.

All depends on your process, equipment etc. All of our internal stuff is cut off the model so we don’t do DXF. External stuff can be DXF, DWG, native whatever…
image.png

[MJuric]

When you say, “that gets broken into multiple pieces” … Do you mean “Save Bodies”..?
(I’ve seen someone do this and then take these saved bodies and “Convert to Sheetmetal” all over again..
That seemed odd to me, just to have separate bodies for individual drawings.)
There are many thing about this methodology I do not understand..

I’m not sure why anyone would “Save bodies”, especially when you can create individual drawings from any multi-bodied part using the “Select body” option. I just think that many people doing this are unaware that you can do this with multi-bodied parts.

I have run into situations where a company has a software that cuts from the models and sometimes you have to break out the individual bodies for them. However, again, in many cases this is because people don’t know how to use their nesting software.

I actually did this with our sister company. They were insisting they needed “One file One part” or their nesting software couldn’t import the parts. I got a demo copy of their software, worked with the VAR and set up a filter for them that took a multi bodied part and imported all the flat patterns based on a particular configuration. This actually made it EASIER on them then having to import multiple different files.

Of course after doing all of this and showing them how to do it they stopped doing it because…“Well it’s not what we used to do”…in other words it’s something new that makes our job easier and would save everyone money…so we aren’t doing it <()>

[mike_miller]

I’m not sure why anyone would “Save bodies”, especially when you can create individual drawings from any multi-bodied part using the “Select body” option. I just think that many people doing this are unaware that you can do this with multi-bodied parts.

I have run into situations where a company has a software that cuts from the models and sometimes you have to break out the individual bodies for them. However, again, in many cases this is because people don’t know how to use their nesting software.

I actually did this with our sister company. They were insisting they needed “One file One part” or their nesting software couldn’t import the parts. I got a demo copy of their software, worked with the VAR and set up a filter for them that took a multi bodied part and imported all the flat patterns based on a particular configuration. This actually made it EASIER on them then having to import multiple different files.

Of course after doing all of this and showing them how to do it they stopped doing it because…“Well it’s not what we used to do”…in other words it’s something new that makes our job easier and would save everyone money…so we aren’t doing it <()>

There are numerous reasons why multibody parts aren’t a good “end-in-themselves”, and why a meat cleaver approach is needed to split them up:

-Cutlists have a very bad habit of resetting themselves and losing data. We have several part files that do this about every 2-3 weeks. Bringing linked values back means regenerating the cutlist which means losing all your custom properties. It. Is. A. Massive. PITA!

-SWX Detailed Cutlist BOMs are a torture chamber. (dissolve subassemblies and parts, combine identical components, attempt to reorder and sort bodies from different parts…fails every time, beat head on desk)

-Title blocks don’t work.

-Using different materials is doable, but fragile. It breaks if the body ID changes, which is DUMB.

-Revision management is difficult if not impossible (which body changed inside this part file anyway?)

-Part/document number schemes become convoluted with some numbers being in cutlist properties and some being in file properties.

-Alternate position views only display parts; there is no option for “Show Bodies”.

[DanPihlaja]

This to me doesn’t look like a weldment. It looks like an assembly of machined and purchased parts with features in folders.

That is exactly what this is. It is my master part. Which is then split apart and re-assembled into an assembly.

If I ever need to modify anything, I just come into this part and modify it, then reopen the assembly and update it.

This is one of 7 master parts that I used for this project.

[matt]

That is exactly what this is. It is my master part. Which is then split apart and re-assembled into an assembly.

If I ever need to modify anything, I just come into this part and modify it, then reopen the assembly and update it.

This is one of 7 master parts that I used for this project.

Yeah, that’s what I thought it was. Hope it works for you.

[DanPihlaja]

Yeah, that’s what I thought it was. Hope it works for you.

It did. The project is complete and the fixture is in the machine. Worked really well actually.
Granted, I spent some extra time splitting apart the master into the components to create the assembly. But I saved a lot of time making changes when/where I needed to and also saved time in the initial design stage.

But it works really well. I wouldn’t do it on a small assembly, but a large one, definitely.

[matt]

I’m answering this from the standpoint of using multi-bodied parts for weldments. I’m not sure why you would use it for parts that are essentially assemblies.

That’s what the picture shows, right? an assembly being modeled as a part.

If you have parts that you want to “Re-Use” or use often you can make templates of them and insert them.

Why break in the back door when the front door is open?

How are you getting library parts into assemblies etc without inserting them? Maybe I’m not understanding this one.

You can’t insert Toolbox library parts/hole wizard with all those advantages into a back door multibody assembly wannabe. You can’t even do multiple instances of a single part in another part, they’re all just separate bodies.

Don’t understand this one either. Configurations in weldments work the same way they do everywhere else.

Yes, but you can’t have a configured part inside another configured part unless the configured part is modeled as a separate part. Or you could but it would be an undecipherable rats nest.

Not sure why. What is harder about making drawings from a multi bodied part versus an assembly or anything else?

Additional steps for each body you do it for, can’t access the drawing directly from the part, no association between the part number and the drawing, no provision for handling multiple instances of a single part, etc.

Don’t understand this at all. You have one part.

you can’t rev one part, you have to rev the whole mess, you can’t reuse one part in another assembly without bringing links with it, there’s just a slew of things you can’t do

Again, not sure why that would be. Everything is in one file. Errors are easily seen and rectified.

if you’ve built features on features a failure of one part can cascade into all the parts. You must know stuff like this?

While you could do motion using multiple configurations, I’m really not sure why someone would use multi-body for an assembly…I mean it’s an assembly not a multi-bodoed part.

??? Your whole argument is in favor of doing assemblies as multibodied parts.

I don’t really agree with this statement. You have a single part that is treated as a single part. Modeling it as a single part is easier from start to finish from modeling thru ERP thru manufacturing.

Maybe you’re leaving out a key piece of information here. You’ve got a set of parts being treated as a single part.

If this is just a purchased subassembly, then I could see making it this way, but I’d skip the multibodies and just make it a single body. If this is a concept that you haven’t any idea how it’s being manufactured then I could see modeling it this way until you figure it out, then this might be a usable workaround. But if these are parts your company designs and manufactures, then you’re forcing it all through the back door when there’s a big wide opening right up front. Simply avoiding an assembly doesn’t give you any benefits. All I can think is that there is some key detail I didn’t get, because it’s just a string of bad ideas trying to force SW to be NX or Acad or something else. Your responsibility for the documentation goes beyond a printed piece of paper. The techniques you show are ok as a workaround when there is some extenuating circumstance, certainly not a go-to method for real production data where there are no barriers to using the software the way it’s designed to be used. Unforced error. Personally I don’t care what you do, but I really don’t want some impressionable person to come here and say “Matt’s site says you can save a lot of fuss by making assemblies as multibody parts”. You can obviously do what you choose, but from a best practice point of view, from a training point of view, from a tech support point of view, from a demo point of view, this is a bad idea. It’s only not a bad idea as a workaround for some issue other than “I don’t like the way it was designed to work”. Remember there are other people who are going to have to use this data after you.

I’m not against multibody modeling, I use it all the time. I’m not against master models, I use those all the time, but for me multibodies are almost always part of a method to get to a single body, or to carry a complex shape across several parts, or a mold die, or one of the established methods like weldments.

I started this thread specifically because I was curious and wanted to talk about sheet metal multibodies. It turns out that I’d still model the sheet metal separately and insert it into the weldment as a part, especially if it has a separate part number, as long as it isn’t just made on the spot.

[MJuric]

There are numerous reasons why multibody parts aren’t a good “end-in-themselves”, and why a meat cleaver approach is needed to split them up:

-Cutlists have a very bad habit of resetting themselves and losing data. We have several part files that do this about every 2-3 weeks. Bringing linked values back means regenerating the cutlist which means losing all your custom properties. It. Is. A. Massive. PITA!

-SWX Detailed Cutlist BOMs are a torture chamber. (dissolve subassemblies and parts, combine identical components, attempt to reorder and sort bodies from different parts…fails every time, beat head on desk)

-Title blocks don’t work.

-Using different materials is doable, but fragile. It breaks if the body ID changes, which is DUMB.

-Revision management is difficult if not impossible (which body changed inside this part file anyway?)

-Part/document number schemes become convoluted with some numbers being in cutlist properties and some being in file properties.

-Alternate position views only display parts; there is no option for “Show Bodies”.

As I’ve said a few times now I’m not sure why someone would use a multi-bodied part to do something that is more like an assembly. I don’t use multi-bodied parts like that. I use multi-bodied parts for purchased parts that are single part numbers even though they are assemblies and may have motion and weldments.

I’ve used different materials in weldments and have never had a problem with it changing it back.

I do alternate position views all the time by using move body and configs. This is how I do all my purchased parts like Cylinders, ball screws etc etc.

Part numbering is easy and automatic for us as we use the file part name combined with the cut list number.

Again, sounds like some of what you’re having problems with is due to trying to using multi-bodied parts as assemblies rather than multi-bodied parts. I never have issues with any of the things you mentioned but I also never dissolve multi-bodied parts and try to combine similar components. We use multi-bodied parts for weldments and on a weldment cut list you don’t try to combine all the parts from multiple weldments into one. The cutlist is for that weldment. Combining similar parts is done at the ERP level not the cutlist for the weldment. If for some reason I had a part I used often inside of a weldment I would make it a library item and insert it. Then at the ERP level combine it. We do this every day with items like weld nuts etc.

I guess in this issue I agree with matt. Don’t try and make the software do something it wasn’t designed to do and you avoid a lot of problems. If the way you use multi-bodied parts doesn’t match how SW had designed them to be used…don’t do that.

I use them day in and day out and they tend to give me less of a hard time than most of the other things I use in SW.

[MJuric]

I’m not against multibody modeling, I use it all the time. I’m not against master models, I use those all the time, but for me multibodies are almost always part of a method to get to a single body, or to carry a complex shape across several parts, or a mold die, or one of the established methods like weldments.

I started this thread specifically because I was curious and wanted to talk about sheet metal multibodies. It turns out that I’d still model the sheet metal separately and insert it into the weldment as a part, especially if it has a separate part number, as long as it isn’t just made on the spot.

I think we are talking past each other here. As I have stated I do not know why someone would use multi-bodied parts rather than an assembly. We use them for weldments and purchased parts. We use them for purchased parts even if they are assembly because that assembly is a single part to us.

My response is to your “Sheet metal multibodies”. If it’s a weldment I use multi-body even if it’s sheet metal. If it’s not, I use an assembly.

Again we do this all the time. Enclosures are sheet metal assemblies because the parts are bolted or fastened together in some way other than welding. In this case each sheet metal part is processed seperatly and then “Assembled”…because it’s an assembly.

If we have a structure that is going to be welded together then it’s a multi-bodied weldment regardless of whether it’s sheet metal etc. In that case the parts are “Pre-bent” and welded and that weldment is the part. All the individual pieces of that weldment are not “Parts” but merely raw material for that weldment. The pieces are no more “Parts” for us than a bar of 6" round CRS stock.

This however also means you have to process weldments like weldments and assemblies like assemblies. Our weldments have a cut list on that weldment, that individual part. Process weldments in this manner and you don’t have any of the issues anyone in this thread is talking about. Try to process a weldment like an assembly and you will have all these issues.

[matt]

I think we are talking past each other here. As I have stated I do not know why someone would use multi-bodied parts rather than an assembly. We use them for weldments and purchased parts. We use them for purchased parts even if they are assembly because that assembly is a single part to us.
…

If we have a structure that is going to be welded together then it’s a multi-bodied weldment regardless of whether it’s sheet metal etc. In that case the parts are “Pre-bent” and welded and that weldment is the part. All the individual pieces of that weldment are not “Parts” but merely raw material for that weldment. The pieces are no more “Parts” for us than a bar of 6" round CRS stock.

Well then I’m confused about why we’re arguing. Purchased assemblies, yeah, I’d do that as a single part.

The only exception I’d add to what you say about sheet metal in a weldment would be if you had a complex sheet metal part that is welded onto a frame. Like an enclosure with a lot of bends and other features. If it’s just a couple of small bends on a bracket, then yeah, just make it multibody.

[MJuric]

Well then I’m confused about why we’re arguing. Purchased assemblies, yeah, I’d do that as a single part.

The only exception I’d add to what you say about sheet metal in a weldment would be if you had a complex sheet metal part that is welded onto a frame. Like an enclosure with a lot of bends and other features. If it’s just a couple of small bends on a bracket, then yeah, just make it multibody.

That’s what I’m arguing. I don’t care about complexity I care about whether it’s a weldment or not. If it’s not a weldment, don’t use multibody. If it is a weldment, use multi-body, lots of complex sheet metal parts or not.

I don’t find one or the other “Harder” or “Easier” to do except how you process it down the line and specific tools available. I’m working on the cabinet below as a weldment. It’s essentially two electrical cabinets that create a roll around cart. Door flanges, mounting blocks, top plate etc. Various parts have pre-machining, pre-bending etc etc. The entire thing then has machining as a weldment. All done as a weldment…because it’s a weldment.

When I bold on the doors, add the power disconnect, interlocks etc…then it’s an assembly