A primer by power users Elise Moss and Daniel Hertzberg.
Daniel Herzberg, who currently runs the Boston SOLIDWORKS User Group, gave a presentation at the recent 3DEXPERIENCE World conference held in Nashville earlier this year. Hertzberg is a fabulous SOLIDWORKS mentor with lots of tricks up his sleeve. If you missed his presentation and you attended the conference (either in person or remotely), you have access to his presentation as well as many of the other classes online at no charge.
For those of you who prefer to read about it, I’ll provide some of the highlights along with some commentary and tips from my personal experience.
Master modeling is used on fixed assemblies where you don’t have to do any motion studies.

For master modeling to be effective, you should be comfortable with the idea of linking dimensions and using equations. You can create the links either at the assembly level, the part level, the feature level, or the sketch level. SOLIDWORKS is wonderfully versatile in that way.

The master model technique involves creating a master model part that has the features and shapes required for the assembly. This master model controls all the components used in the assembly.

To create and edit equations, go to Tools→Equations.

I start by adding global variables. Because they are “global,” they can be used in any part in the assembly.
These can be modified and more variables can be added as your design takes shape.
Next, I enable Link to the external file.

I can create a new text file and all my variables are automatically added to the file.
This file can then be referenced by any part or assembly model.
Click Link to link the text file to the active model.

Once the file is linked, the file name and path will be displayed in the equations dialog box.

You also have the option of modifying the text file, saving it under a new name, and then using the browse and open buttons to replace the currently linked file.

You can open the linked text file using Notepad. Notice that each variable is on its own line. Each variable name is in quotation marks.

Once you have designated a linked file, the variables in the equations dialog will be grayed out. This is because they are controlled by the text file.

So that the master part can drive features of any of the children components, be sure you add a link to any relevant values. Simply click on the master part, click on the extension line of a dimension, and then right-click and select Link Values. Then, select the relevant variable.
Many users are unaware of this, but you can insert a part into a part document. Keeping in mind that the master model is the template for all parts in the assembly, you can insert the master model part into all the part files you need to create.

You start with a new Part file. Then go to Insert→Part.

Review all the features you can include when you insert a part.

If you select the green checkmark, the master part should be placed so that it aligns with the origin and all the planes are aligned.

To bring in the equations to the new part, go to Tools→Equations. Enable Link to the external file and select the file you created earlier. You will see a preview of the equations and can now click Link.

You can use the offset plane to cut away the top of the master part in the part you set as the bottom. Select the Intersect tool from the Features ribbon.

Select the offset plane that is cutting the part and select the part. Enable Create both and then select to remove the top of the box.

Next, you will shell the bottom part using the Global Variable for the ShellThickness.

The payoff comes if you make changes to the master model or the equations text file. Modify the master model and any changes you make will automatically be reflected in the parts where they have been inserted.
How much detail you want to include in your master model depends on the assembly and the design’s intent. The more detail you include in the master model (i.e., the more features), the slower your rebuild time is going to be. That said, you only need to update or make changes to your master model, and then the changes will flow down to all the components that make up the assembly. You also can include sketches in your master model that can be leveraged to create features—such as sweeps or hole patterns. These might be easier to maintain in the long run.
As a designer, you know that the only certainty in a design is that it will be changed, so use your experience to guide how complex you make your master model with the understanding that anything you leave out will have to be maintained in the individual part. I would include any mating features in the master model as a basic design rule just to ensure that components fit together properly.
Because you are assembling the parts so that each part is fixed and placed relative to the origin, this will speed up your processing time, but it also means that the master model is driving how components are located in relation to each other, so be sure you take that into consideration as well when planning your design.

If you like the idea of using a master model to drive the components in your assembly, you may want to create your own master model Toolbar. That way, all the tools you will be using in the master model process will be easily accessible.

Right-click on a blank space on the ribbon and select Customize.

A new tab is added to the command manager. Right-click on the New Tab and select Rename Tab.

Select the Commands tab in the Customize dialog box.
Use the Search field to locate the commands you want to add to the master modeling ribbon.
Then drag and drop each desired command to the new ribbon.
If you grab the wrong command, just drag and drop it back to the Commands window.

To add a dividing line to organize your tools, simply right-click at the location where you’d like to add the dividing line and select Begin a Group.
In the presentation, one of Hertzberg’s examples was how to create an assembly for a Star Wars lightsaber using the master modeling method.
He started by downloading an image of a lightsaber handle from the Internet and using the image as a template for his model.
To do this, start a new part file.
Start a sketch on the front plane.

Type “sketch pi” in the search field located next to Help and the tool for Sketch Picture will be listed.

This tool allows you to use any image file.

I positioned my image so that it correlates with the origin. You can use the grips around the frame to rescale the image.

I renamed the sketch, so that it is easy to identify what the sketch is.

The first feature is the cylinder that makes up the main shaft of the lightsaber. I can use the image to guide me on how tall to make the cylinder.

When I am done with my master model, I have all the main components outlined. Then it is just a matter of inserting my master into each part and replicating the desired features for each part.
Once you have the master model, you can use Treehouse to plan out your assembly structure. Treehouse is especially useful in a team environment because you can assign different parts to team members and because the team is using the same master model, you are guaranteed that all the parts will fit together properly.

Treehouse is a freebie application that comes with SOLIDWORKS. You can perform a search in your applications menu to locate the program and launch it from there.

Use Settings, located at the bottom right of the Treehouse dialog, to define which templates to use for your SOLIDWORKS documents.

You can set up the parts, subassemblies and drawings you will need, including adding any custom properties.


Once you have set up your drawing tree, you can export all the documents over to SOLIDWORKS. This will automatically create blank files with the custom properties you defined. Insert your master model into the part document and go from there.
Hertzberg’s presentation, as well as a few other presentations on master modeling, can be accessed for free from the 3DEXPERIENCE World website. I encourage you to block out a lunch hour, eat lunch at your desk and watch his presentation. It is well worth it.
If you want to give master modeling a whirl, start with a small assembly or subassembly, and try it out using some of the tips outlined here. See if you can get your team to join you. You may find that this will actually boost your efficiency and reduce errors.