AI for CAD Tools
Compare generative design software by manufacturing method: Fusion, Creo GDX, NX, Simcenter Inspire and nTop, plus a two-week test on your own parts.
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5 min read
Michelle Ben-David
Michelle Ben-David is a mechanical engineer and Technion graduate. She served in an IDF elite technology and intelligence unit, where she developed multidisciplinary systems integrating mechanics, electronics, and advanced algorithms. Her engineering background spans robotics, medical devices, and automotive systems.
BOTTOM LINE
Pick generative design software by the manufacturing method your parts use. Fusion documents additive, milling, 2-axis cutting and casting constraints, while Creo GDX, NX, Inspire and nTop differ in runtime and returned geometry. Test 3 real parts with and without a process constraint, and search your PLM for an existing part first with Leo.
Choose generative design software by the manufacturing method your parts use, because each tool constrains outcomes for a different set of processes. Autodesk Fusion documents constraints for additive, milling, 2-axis cutting and casting, while Creo GDX, NX, Simcenter Inspire and nTop differ in where they run and what geometry they return.
If your team machines most parts on 3-axis mills and buys castings from a foundry, an unconstrained topology result is a concept sketch, not a release candidate. The sections below sort the tools by process, compare six options in one table and give a two-week test to run on your own parts.
Five criteria separate generative design tools for a team
A single engineer judges a result by its shape. A team also lives with what the tool constrains, what geometry it returns and how each study is billed. Score every candidate on these five criteria.
Manufacturing constraints. Fusion's documentation says constraints typically limit shape freedom and give less performant designs, so the tool must offer the process your shop actually runs.
Returned geometry. Siemens describes NX as working on combined facet and B-rep data. Simcenter Inspire mixes BRep, PolyNURBS, facets and implicit geometry. Ask what lands in your CAD: a feature tree, a BRep or a mesh.
Where the study runs and how it is metered. Creo GDX is a cloud solution and shows estimated credits before you click Generate.
Fit with the tools you own. nTop's documentation says it is designed to work alongside existing CAD, CAE and PLM tools.
Who can set up a study. Siemens keeps the engineer responsible for specifying requirements and evaluating options, so budget senior review time for every study.
IN PRACTICE
The geometry search has been invaluable, helping me find standard parts instead of designing new ones, saving a huge amount of time and effort. The search system is smart and CAD-aware.
- eytan s., R&D Engineer
Six options compared on process, geometry and runtime
Each cell comes from a vendor page linked in Sources, read on 8 November 2026. A dash means the page does not say.
Option | Process constraints named | Geometry and runtime | Data it reaches | Best for |
|---|---|---|---|---|
Autodesk Fusion Generative Design | Additive, milling (2.5-, 3-, 5-axis), 2-axis cutting, casting, unrestricted | One outcome set per selected method; runtime not stated | Designs in the Fusion Generative Design workspace | Teams already modeling in Fusion |
PTC Creo GDX | Several materials and manufacturing constraints in one batch | Cloud solution; credits estimated per run | Uploaded studies | Creo teams that want a batch of alternatives |
Siemens NX | Manufacturing methods listed as a study input | Topology optimization on combined facet and B-rep data | - | NX teams |
Simcenter Inspire | Manufacturability tools for casting, extrusion, forming, molding and 3D print | BRep, PolyNURBS, facet and implicit geometry | - | Designers who want simulation beside modeling |
nTop | - | Implicit modeling | Works alongside existing CAD, CAE and PLM tools | Teams ready to model with implicit geometry |
Leo | None: not a topology optimizer, no FEA or CFD | Editable CAD with a feature tree in SolidWorks, Creo, Inventor or Onshape | Windchill, Teamcenter, SolidWorks PDM and Autodesk Vault, in the folders you choose | Finding an existing part before a study starts |
Siemens' Inspire page announces that former Altair products joined Simcenter in June 2026, so quotes may carry either name.
Each tool constrains a different set of processes
Autodesk Fusion. Fusion lists five methods: unrestricted, additive, milling, 2-axis cutting and casting. Every selected method returns its own set of outcomes, and additive adds one set per build direction (X+, Y+, Z+). Casting accepts minimum thickness, uniform thickness and draft angle. Fusion's page suggests adding an unrestricted run to measure what each constraint costs in performance.
Creo GDX. GDX generates several results with different materials and manufacturing constraints in one run. The credit estimate appears before generation, so a manager sees consumption per study. For the study steps, read the Creo GDX walkthrough.
Siemens NX. Siemens describes topology optimization embedded in NX on combined facet and B-rep data, which it calls convergent modeling. A team that must return results to a parametric model should test that path first. A worked NX setup shows the study inputs.
Simcenter Inspire. One environment covers modeling, generative design and manufacturing simulation, and the Siemens page lists casting, extrusion, forming, molding and 3D print tools. For a team without a simulation specialist, the draw is staying in one tool. Confirm licence packaging after the June 2026 change.
nTop. nTop's documentation names implicit modeling as its core, with geometry that stays stable across the full design space. The cited page does not say how results return to your CAD, so put that question to the vendor.
A two-week test on three parts, with pass criteria
Use released parts, so every result has a baseline mass and a validated stress report.
Choose 3 released parts: a milled bracket, a cast housing and a printed fitting. Record each part's mass and validated peak stress.
Write one brief per part with envelope, load cases, material, process and target safety factor. Every tool gets the same brief.
On each tool, run one unconstrained study and one study with your shop's process. Pass: both finish inside week 1. The CNC machining constraints and additive constraints posts list typical inputs.
Send each constrained result to the person who will machine, cast or print it. Pass: they accept the geometry, or they list the changes with hours attached.
Import each result into the CAD that owns your drawings. Pass: the geometry edits cleanly, or the written conversion routine takes under 1 hour per part.
Check the loads again in your validated solver. Pass: peak stress stays under the allowable value and mass does not exceed the baseline.
Review effort grows with the number of methods. This count assumes one outcome set per selected method and one per additive build direction, as Fusion's page describes.
Study option | Outcome sets |
|---|---|
Unrestricted | 1 |
Additive, 3 build directions (X+, Y+, Z+) | 3 |
Milling, 3-axis, 1 configuration | 1 |
Casting | 1 |
Total for one part | 6 |
Total for 3 test parts | 18 |
Cut study options before you run them, not after: each unneeded option adds at least 1 set per part to the review.
Search your PLM for an existing part before any study runs
Run the first step of the test with Leo, before any solver. Give Leo the part's requirement in words, a STEP file or an installation space. Leo searches your connected PLM or PDM first, then a vendor-parts catalog, using geometric search. You choose which folders, projects or teams it reads.
For each of the 3 test parts, count the released near matches Leo returns. Each match removes up to 6 outcome sets from the review above. When nothing fits, Leo generates an editable starting part from text, images or a drawing and rebuilds it with a feature tree in SolidWorks, Creo, Inventor or Onshape.
One limit: Leo is not a topology optimizer and runs no FEA or CFD, so loads still go through the tools compared here. Data handling is documented on the security page.
FAQ
Manufacturing methods in the Generative Design workspace, Autodesk, accessed 2026-11-08
Generative Design Extension, PTC, accessed 2026-11-08
Generate Designs, PTC, accessed 2026-11-08
Generative design, Siemens, accessed 2026-11-08
Simcenter Inspire software, Siemens, accessed 2026-11-08
nTop documentation, nTop, accessed 2026-11-08
Leo AI FAQ: AI for Mechanical Engineering, Leo AI, accessed 2026-11-08
Leo AI security, Leo AI, accessed 2026-11-08
Test Leo on your own parts
See which parts already exist before you run a study
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