Shannon McGarry
Avoid broken mirror and pattern results in Fusion by learning when to use Optimized, Identical, or Adjust compute options for accurate outcomes.
Elevate your design and manufacturing processes with Autodesk Fusion
When working with mirror and pattern features in Fusion, you’ve likely encountered a frustrating scenario: you select the default “Optimized” compute option, the preview shows exactly what you want, but when you click OK, the result doesn’t match your expectations. Understanding the three compute options available can help you choose the right one from the start and avoid these issues.
The three compute options
Fusion offers three compute types when creating patterns and mirrors:
- Optimized
- Identical
- Adjust
Each option handles geometry differently and is suited for specific situations. Let’s explore how each one works and when to use it.
Optimized: Fast but limited
Optimized is the default compute option and the fastest of the three. It creates identical copies by patterning the feature faces rather than recalculating the entire operation.
When optimized works well
This option is great for simple geometry that connects parts repeated multiple times in a design, especially when your timeline frequently changes. The faster recompute time makes it ideal for designs in active development.
When optimized fails
Consider a simple example: you create an extruded column with a join operation on top of a base cube, then pattern it in a 3×3 grid. The preview shows nine columns as expected, but the result only produces three.
Why does this happen? Fusion cannot calculate how the faces create a body without including the same face from the original base cube that wasn’t selected in the pattern. Optimized only patterns the selected feature faces, so it lacks the geometric information needed to properly join the patterned features to the base.
Identical: More reliable, still fast
The Identical compute option offers a middle ground between speed and reliability. It creates identical copies by replicating the results of the original features rather than just patterning faces.
Key characteristics
When you use Identical on that same 3×3 column pattern, you get all nine columns as shown in the preview. However, there’s an important distinction: each patterned instance becomes a separate body. Only the original column joins to the base cube. The other eight columns are standalone copies of just the column geometry.
The Identical option computes the shape of the object rather than the complete operation, which means join operations from the original feature don’t carry through to the patterned instances.
Best use cases
Identical is ideal when you’re creating geometry that’s likely to change during design iteration. It’s more reliable than Optimized and less likely to cause errors, while still maintaining good performance.
Adjust: Maximum flexibility, maximum computation
The Adjust compute option is the most powerful and computationally intensive choice. It creates potentially differing copies by patterning both the features and calculating their extents or terminals.
How adjust handles operations
Using the same column pattern example with Adjust produces interesting results:
- The first body remains the original column joined to the base
- The next two columns join to the base cube
- Three individual solid columns appear as separate bodies
- The final three columns join to the opposite side of the base cube
Adjust mimics the join operation of the original feature, applying it intelligently across the pattern. This requires significantly more computational power but handles complex situations that the other options cannot.
The power of adjust with offset features
Adjust becomes particularly valuable when mirroring or patterning features that use offsets from surfaces.
Consider this example: you have a solid block with a curved bottom surface. You create a hole using an extruded cut with a 10mm offset from that curved surface. When you mirror this feature across a midplane:
- Optimized produces a simple mirror of the hole
- Identical produces the same simple mirror
- Adjust creates an extended hole that maps to the offset of the curvature on the opposite side
The Adjust option recalculates the offset relationship, creating a hole that properly follows the curved surface geometry on the mirrored side. This intelligent adaptation to the geometric context makes Adjust essential for complex designs.
Choosing the right option
Here’s a quick reference for selecting the appropriate compute type:
| Compute Option | Speed | Reliability | Best For |
|---|---|---|---|
| Optimized | Fastest | Limited | Simple geometry, large patterns, frequently changing designs |
| Identical | Fast | Good | Geometry likely to change, when you need separate bodies |
| Adjust | Slowest | Highest | Complex situations, offset features, when operations need to adapt to context |
Universal application
These compute options work consistently across all pattern and mirror types in Fusion, including:
- Rectangular patterns
- Circular patterns
- Path patterns
- Mirror features
Whether you’re creating a simple linear array or a complex circular pattern, understanding these compute options will help you achieve the results you need on the first try.
Getting started
The next time you create a pattern or mirror in Fusion, take a moment to consider which compute option best fits your situation. Start with Identical as a reliable default, use Optimized when performance matters and geometry is simple, and reach for Adjust when you need features to intelligently adapt to their geometric context.
By selecting the right compute option from the start, you’ll spend less time troubleshooting unexpected results and more time designing.
Frequently asked questions
Compute options control how Fusion recreates geometry when you mirror or pattern features. The three options, Optimized, Identical, and Adjust, determine whether Fusion copies faces, replicates results, or recalculates full feature operations.
This usually happens when using the Optimized compute option. The preview shows a visual approximation, but the final result may fail because Optimized only patterns selected faces and lacks full geometric context for joins or interactions.
–Optimized: Fastest, patterns faces only, limited reliability
–Identical: Replicates feature results, more reliable, creates separate bodies
–Adjust: Recalculates full operations, highest accuracy, slowest performance
Use Optimized for simple geometry, large patterns, and designs that change frequently where performance matters more than complex feature interactions.
Use Identical when you need more reliable pattern results and expect geometry to change. It’s a good default choice for most workflows but may create separate bodies instead of joining them.
Use Adjust for complex designs, especially when features rely on offsets, surfaces, or need to adapt to surrounding geometry. It ensures operations like joins and offsets behave correctly in patterns or mirrors.
Yes. Optimized, Identical, and Adjust behave consistently across rectangular, circular, path patterns, and mirror features.
Identical is often the best default. It offers a balance of performance and reliability without the limitations of Optimized or the heavy computation of Adjust.