Train your brain to use Auto Constrain

Sketching in Fusion is an essential skill for creating precise models. But manually adding all constraints takes time and effort. That's where the Auto Constrain feature shines. This AI-powered tool helps you quickly make your sketches fully constrained and ready for modeling.

What Is Auto Constrain?

Auto Constrain is a special button in Fusion that automatically adds dimensions and constraints to your sketch. It uses AI technology to analyze your shape and guess what constraints are needed. Instead of dragging lines and trying to add constraints one by one, you just click and let the software do the work.

How Does Auto Constrain Work?

Once activated, Auto Constrain reviews your sketch and applies a set of constraints. It tends to keep the shape in shape while adding dimensions. The goal is to make sure every part of the sketch is fully defined, so it doesn’t move or change unintentionally.

Why Use Auto Constrain?

Auto Constrain speeds up the design process. It helps you create fully constrained sketches faster and with less frustration. You won’t accidentally forget constraints, which can lead to errors later. Plus, it’s a great way to learn which constraints are most important.

How to Use Auto Constrain Effectively

Preparing Your Sketch

Before you hit Auto Constrain, draw your shape roughly. It’s best to set a few key constraints that help guide the AI. For example, sketch basic lines and points, and fix known dimensions. Fixing common mistakes that might trip up the tool can make its results more accurate.

Applying Auto Constrain in Fusion

Once your sketch is ready, click on the Auto Constrain button. Fusion then adds constraints and dimensions automatically. You will see different results pop up. Sometimes, there are multiple options for how constraints could be applied. Pick the one that makes the most sense for your design.

Getting the Best Results

Use the "Generate More" option if you want to see more possible constraints. This allows you to compare different ways Fusion can solve the sketch. Once you find a result you like, lock in the dimensions and constraints by confirming. The software will then show a fully constrained sketch with a lock symbol.

Tips and Tricks for Better Auto Constrain Use

Creating Better Initial Sketches

Draw with intention. Keep lines simple and avoid complex intersections. Adding reference lines or axes early on makes auto constraints more accurate.

Refining Auto Constrain Output

After auto constraining, manually adjust key dimensions. Use FX formulas to make dimensions linked. For example, setting two dimensions to always stay equal.

Managing Constraints and Dimensions

You can limit how many constraints are added by dragging a slider. This helps keep sketches simple. Use “Set datum” to fix a specific point in space. When the sketch isn’t fully constrained, check which constraints are missing or broken and fix them manually.

Conclusion

Auto Constrain in Fusion is a powerful tool to speed up your workflow. It helps you create fully constrained sketches without overthinking the details. When used well, it makes designing faster, cleaner, and less error-prone. Experiment with it regularly and watch your modeling efficiency grow. The more you use it, the more intuitive it becomes.