MultiBody and Master Model Techniques

[matt]

Multibody modeling is the stepping off point for many kinds of work. It is not a replacement for assemblies. The end product can be a single part, it can work in lieu of in-context modeling, you can go from multiple parts to a single part or from a single part to multiple parts through multibody techniques. For some kinds of modeling, multibody is a must. For others, its a no-no. Visualize how to best apply these tools in your own design and modeling process as you go through this 34 page document excerpted from my Mastering SolidWorks book.

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Master Model Techniques are where you model multiple parts for an assembly in a single part, and then break bodies out to multiple parts. There are many different scenarios where this is most appropriate, but if you think of a car body, you would not model the door as a separate part from the fender, the hood, the roof, etc... you would model the entire shape as a single part, and then break it into multiple bodies, then multiple parts where you add detail, then bring it back into a single assembly.

There are a lot of ways you can do all of this, and as many ways as there are projects. This 14 page excerpt from the Mastering SolidWorks book will get you started in employing these techniques.

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[Jeremy Savage]

Thanks for sharing Matt! I am looking for a good indepth tutorial (video) to share with my coworkers on the master model approach. Do you know any good resources for this? I would like it to really get into the details once the part is past the save bodies step. Thanks

[matt]

Thanks for sharing Matt! I am looking for a good indepth tutorial (video) to share with my coworkers on the master model approach. Do you know any good resources for this? I would like it to really get into the details once the part is past the save bodies step. Thanks

Um, I just excerpted (for free) two big chapters out of my book on the topic.

After the save bodies step, you just add features in the individual parts that you saved the bodies to. When you need to do an update, you go back to the master model, make the change, open the child parts and make sure everything rebuilds.

Then you put the parts back together in an assembly. All the parts have the same origin because they all came from the same place to start.

Tell you what, if you buy the book, you can get all those example parts and some movies on the topic as well.

Or I have a new chapter on the topic in my subscription surfacing site.

Or I can give you youtube links to 20 videos you can't understand and show you stuff you already know probably using models they didn't make.

[zwei]

Beside Matt's bible, another hidden gem (resource) on master modelling is Spanner SOLIDWORKS Webcast Ep 17 & 18

https://www.spannerpd.com/solidworks-webcast-episode-17
https://www.spannerpd.com/solidworks-webcast-episode-18

[Jeremy Savage]

Thanks for sharing those chapters in your book Matt, I have downloaded them and will review. I am very familiar with the methods you are describing. But I will also be buying the book and subscribing. You have alot of helpful info!

I may not have explained myself as well as I could have in my first post. I was looking for a video tutorial series to share with co workers so that they can also learn these methods. I have found that they do not want to read up on this and I thought a complete tutorial walkthrough would be easier for them to watch. I could teach them, but unfortunately sometimes they need to hear it from someone else instead of their direct peer.

[matt]

I may not have explained myself as well as I could have in my first post.

Yeah, I think I got it. You want advanced high quality training materials for free. Did I get that?

[Jeremy Savage]

Not at all, I wasnt asking for free material. Glad to pay for quality material.

[berg_lauritz]

I would love to read it, but I cannot:

Information
You don't have the permission to download files from the Download System

[matt]

I would love to read it, but I cannot:

Ok, that sounds like something I can fix, give me a minute...

[MJuric]

Um, I just excerpted (for free) two big chapters out of my book on the topic.

Excuse my ignorance on the subject but are "Master Model" and "SSP" interchangeable?

Just curious. I've tried to wrap my head around SSP a couple times and have failed miserably each time. Something about the concept just is not ticking the right boxes. If your book has SSP in it I might get a copy...besides I could really use some reading material on surfacing as well.

[matt]

Excuse my ignorance on the subject but are "Master Model" and "SSP" interchangeable?

Just curious. I've tried to wrap my head around SSP a couple times and have failed miserably each time. Something about the concept just is not ticking the right boxes. If your book has SSP in it I might get a copy...besides I could really use some reading material on surfacing as well.

SSP is essentially working with layout sketches and planes to make a multibody part. It is one way to make a master model. Every example I've ever seen has been very 2D, meaning that you can capture all or most of the relationships with 1 or 2 2D layout sketches. It works great for cabinets, and for mold dies. The technique existed long before it was assigned a name and people started claiming to have invented it.

Generally when I talk about master models, it's more like designing the body of a car as a single part, and then using sketches or surfaces or planes to split the single car body model into multiple bodies of the hood, fenders, roof, trunk, etc., and then splitting the bodies out to individual part files. Then you can add features to the individual parts and bring them back together in an assembly. They all have the same origin because they all came from the same part. If you need to make changes to the big overall shape, you go back to the original part and the changes propagate into the child documents. It also helps you segment the rebuild load so that you never have to rebuild the entire tree at once.

Master model techniques came to be probably with Pro/E and maybe even earlier with CV. I've used the method on simple 2 part assemblies up through more complex stuff. Usually not complex in the number of parts, but in the number of features, some with hundreds or thousands of features, and few if any flat faces. I've done models like reading glasses, cricket bat, medical device housing, joystick, molds and casts, plastic parts with removable panels, lots of sample parts...

There are a lot of different ways of working with the master model technique. You can do solids, surfaces, and there are 4 different tools to move the bodies from multibody to individual part files which have different uses, advantages and disadvantages. In the "Episodes" surfacing training site, I have a chart that goes through and compares the capabilities of the 4 master model methods.

It's a huge topic, and every time you use the technique, you probably do it slightly differently.

I had one part that was so complex that I made all of the reference surfaces in one model, broke that out to separate models where I made all the details, then brought it back together in a single part. I did this to compartmentalize the feature rebuilds and errors, so one error didn't blow up the whole thing, and also so you could wait 3 minutes to rebuild just the section you were working on, but you didn't have to wait 20 minutes to rebuild the whole feature tree ( with 2400 features).

[MJuric]

SSP is essentially working with layout sketches and planes to make a multibody part. It is one way to make a master model. Every example I've ever seen has been very 2D, meaning that you can capture all or most of the relationships with 1 or 2 2D layout sketches. It works great for cabinets, and for mold dies. The technique existed long before it was assigned a name and people started claiming to have invented it.

Maybe that's why I can't get my head around it. Almost nothing I do can be defined by a few layout sketches. I've just not been able to figure out how it would work for doing things like machines with multiple motions and Axii.

Generally when I talk about master models, it's more like designing the body of a car as a single part, and then using sketches or surfaces or planes to split the single car body model into multiple bodies of the hood, fenders, roof, trunk, etc., and then splitting the bodies out to individual part files. Then you can add features to the individual parts and bring them back together in an assembly. They all have the same origin because they all came from the same part. If you need to make changes to the big overall shape, you go back to the original part and the changes propagate into the child documents. It also helps you segment the rebuild load so that you never have to rebuild the entire tree at once.

Master model techniques came to be probably with Pro/E and maybe even earlier with CV. I've used the method on simple 2 part assemblies up through more complex stuff. Usually not complex in the number of parts, but in the number of features, some with hundreds or thousands of features, and few if any flat faces. I've done models like reading glasses, cricket bat, medical device housing, joystick, molds and casts, plastic parts with removable panels, lots of sample parts...

There are a lot of different ways of working with the master model technique. You can do solids, surfaces, and there are 4 different tools to move the bodies from multibody to individual part files which have different uses, advantages and disadvantages. In the "Episodes" surfacing training site, I have a chart that goes through and compares the capabilities of the 4 master model methods.

It's a huge topic, and every time you use the technique, you probably do it slightly differently.

I had one part that was so complex that I made all of the reference surfaces in one model, broke that out to separate models where I made all the details, then brought it back together in a single part. I did this to compartmentalize the feature rebuilds and errors, so one error didn't blow up the whole thing, and also so you could wait 3 minutes to rebuild just the section you were working on, but you didn't have to wait 20 minutes to rebuild the whole feature tree ( with 2400 features).

I've used a similar approach when I did some reverse engineering although certainly not all that complex. It was much easier to grab the "Bulk Body", details etc etc and draw it as a single body/Part and then split it up in some cases then it was to try and reverse engineer all the individual pieces and get them to fit together. Saved time as well because you had to reverse engineering half as many surfaces and features.