Part 3: Advanced Tips & Tricks

UML Diagrams Guide

UML diagram best-practices

When sharing your diagrams with others, you want to make sure they’re easy to understand, clean, and follow consistent rules. These factors won’t change your actual model, but they will greatly improve your ability to communicate your system and goals to your team.

Keep fonts & colors to a minimum

Readability is important for understanding. When viewing your diagram, all text should be large enough to be legible. If the text can only be read when zoomed in, your diagram has too much information or is too complicated.

Also, don’t try to get too fancy with fonts. Generally, you can stick to one font type. If you feel confident in your typography skills, you can venture into two or even three, but never add fonts just for the sake of looks. If your designs aren’t adding to the readability of your diagram, they’re taking away from it.

Colors can be a great way to show differentiation in your diagram. It can increase readability and make your diagrams look more professional. However, when taken too far, color can distract your reader from the information at hand or even confuse the reader if not applied uniformly. When using color, think sparingly. Try to stick to the least number of colors necessary to bring clarity to your diagram. It can also be useful to provide a key or legend for colors.

Less information is more useful

Diagrams should focus on just a few key elements with a limited perspective. If you try to include too many elements in your diagrams, they can quickly grow so large and complex that they become too difficult for anyone to actually read.

Large diagrams don’t convey more information; they create more confusion. For complex systems, split information up into smaller, more easily digestible diagrams.

When thinking about how much information to include or exclude, imagine what your diagram would look like printed out on a standard sheet of paper. If it would be too difficult to read, scale back and try again.

You also don’t have to name every attribute, association, or constraint contained within a diagram. Only display items that are relevant to the current perspective of the diagram. That information can be elaborated on within a separate diagram.

Lines should never cross

No two lines in your diagram should cross. This is important not only for clarity, but to ensure that your system does not contain a design flaw.

If you are unable to uncross two or more lines on your diagram, you either have:

  1. Too much information in one diagram. Maybe you’re trying to combine two different perspectives, or you’re just trying to go too in-depth for a single diagram. Remember, less information is often more useful.
  2. A design flaw in your model. The worst case scenario is that your system contains a design flaw, but it’s better to figure that out now than later. All working systems can be displayed without crossing lines. If you’re finding it a challenge to visualize your system, try figuring out if there’s an element you’ve overlooked.

Use right angles

All lines in your diagrams should run either horizontal or vertical. All angles should be right angles. Straightening out your lines will instantly add clarity to your diagrams.

The only exception to this rule is use cases, which sometimes use angled lines to represent relations.

Parents over children

When drawing hierarchies on a diagram, always place parent elements higher than child elements so that arrows will always point upwards.

Most follow this rule without even learning it, but every once in awhile, someone tries to flip their hierarchies upside down. For consistency’s sake, always put parents first. Your reader shouldn’t have to orient themselves to new rules to understand your flow.

If you have multiple elements descending from the same parent, use a vertical tree style to demonstrate your hierarchy.

Keep it consistent

Consistency extends beyond fonts and colors. When you’re done with your diagram, run a quick check to make sure you’ve treated every element equally.

  • Always double check to make sure your elements are aligned, either by one side or by their centers.
  • Make sure elements of the same type are the same size, when possible.

UML diagrams are only as useful as they are readable. If your audience doesn’t understand them, you’ve wasted everyone’s time. Following these rules will ensure that you’re delivering organized, clean diagrams that any team member can pick up and understand.

Choosing your UML diagram tool

If your UML diagram needs to be presented to others, you’ll likely need some kind of app or software to build it out.

Here are some things to consider when choosing a tool:

What are its sharing capabilities?

If you want others to view, comment on, or even edit your diagrams, you need to see what options your tool provides for sharing.

If you can only share diagrams with others who have the program installed on their computer, this can be quite limiting. If it’s a cloud-based tool, check to see if others will need a login to see your work.

When it comes to exporting, what are your format options? What about embedding your wireframes directly onto a webpage?

Each tool has its benefits and drawbacks. If sharing is a priority for you, figure out who you can share diagrams with, who can comment on them, and who can edit them.

Does it allow for collaboration?

Some programs require you to export your files to your teammates to collaborate. This makes version tracking difficult, and it can slow your process down when you’re waiting for someone to get back to you about a particular part of your flow.

Meanwhile, other programs offer simultaneous editing, where you can work together with people, in real time on the same diagram.

If you’re working alone, maybe collaboration isn’t an important feature for you. But if your team needs to regularly access and edit files together, this can be a crucial time saver.

What platform is it available on?

Again, if you’re working with a team across multiple devices, you’ll likely want a cloud-based product that allows easy access to your whole team no matter where they are.

If you’re working alone, a downloaded program might be fine. Just don’t get caught without your computer if you need to make some last minute updates.

Do you need offline access?

Web-based products may not be the best choice for people who often find themselves working out of range of a working internet connection.

Nowadays, with public WiFi connections and hotspots becoming more widely available, this is less of an issue than it was in the past, but some still find this a hindrance under certain circumstances.

What kind of pre-made templates are available? Can you create your own?

Creating UML diagrams entirely from scratch isn’t necessary. You probably have a few favorite templates that you like to start with and shapes you know you’ll want to use. Check out what kind of templates each tool has to offer.

Moreover, see if it’s possible to create or upload your own templates and shapes. Customizing your library of available templates will speed up your workflow, especially when you’re designing a large number of wireframes for a big project.

Why choose Cacoo for creating UML diagrams?

You need the right tool at the right time to make great designs. That’s why it’s important to consider how diagramming tools fulfill your specific needs, rather than just reviewing an exhaustive list of features.

Cacoo is simple to use, easy to learn, and accessible from anywhere with an internet connection. Cloud-based diagramming allows you and your team to collaborate on diagrams in real-time, and share them with important stakeholders without them needing to download any programs or even sign up for an account.

You can create diagrams in minutes; not just UML diagrams, but flowcharts, mind maps, sitemaps, network diagrams, wireframes, and more.

Cacoo can help organize your workflow. With our Team Plan, you can save diagrams into individual Projects, share diagrams automatically with groups, and get feedback in comments right in the app.

You’ll also get:

  • Advanced exporting options (PNG, PDF, PPT, PostScript, or SVG)
  • Revision history (see what changes were made and when)
  • In-app chat (and commenting)
  • Easy sharing (no downloading needed)
  • Diagram embedding (embed diagrams into any webpage)
  • Team management (invite people to your Organization, create groups, and assign roles)
  • Advanced security (manage access to diagrams, so you know exactly who’s seeing it)

Try it out for yourself with our free 14-day trial. You can create diagrams, invite your team, and see if Cacoo is the right tool for you. No credit card required. No risk involved.

We also offer a Plus Plan for those who don’t need our collaboration features but are still interested in the joining the 2.5 million users who depend on Cacoo for their diagramming needs.

Additional Cacoo Resources:

Ready to start wireframing?

Get Started