CPE TPMS
Working public beta

Screening a TPMS lattice tradeoff before running FEA

I built this for the awkward stage where a full FEA or CFD setup is premature, but “this looks printable” is not enough. It uses closed-form models to expose stiffness, porosity, and LPBF feature conflicts in milliseconds.

Try the example Explore the 3D lattice
No signup · Seven TPMS topologies · Thirteen LPBF metals · Early-design screening only

Try the actual model here

Edit the sentence or run the built-in titanium lattice case as written.

Deterministic phrase parser → geometry and lattice screening
Gyroid lattice changing from a sparse to a denser structure in the interactive playground Interactive artifact: change topology, density, and material

What this is and why it exists

CPE TPMS is a browser-based early-design screening tool for metal additive manufacturing. It ranks seven TPMS lattice families, checks representative LPBF feature limits for thirteen metals, and runs idealized structural, thermal, and straight-passage fluid calculations.

The intended gap is between an unsupported first guess and a full Ansys, nTop, or other numerical workflow. The result should help decide which candidates deserve detailed modeling; it is not a shortcut around validation.

Two implementation choices are deliberate. The plain-language input uses a deterministic parser rather than an LLM, so its supported vocabulary can be inspected. The physics runs from closed-form relations rather than a hidden solver, so the assumptions and failure modes can be stated alongside the result. When stiffness and porosity cannot both be reached, the tool reports the conflict instead of returning a generic green check.

Start without code

Choosing a TPMS lattice is not just a matter of picking the most familiar shape. A candidate that looks promising may fail a minimum stiffness target, miss a porosity requirement, or require walls that are too thin for the intended LPBF process.

Open Describe Your Part and enter a normal sentence:

I have a titanium cylinder, 50 mm diameter and 100 mm long. Find a lattice with at least 70% porosity and 5% of the bulk material stiffness.

The site first shows what it understood: material, shape, dimensions, and requested analyses. Check that interpretation before reading the calculated results.

Targets met

Schwarz-D candidate

Both minimum requests are satisfied under the current analytical coefficients.

Solid volume29.6%
Porosity70.4%
Cell size4.05 mm
Wall estimate0.60 mm
Tradeoff required

Raise stiffness to 20%

The lattice needs substantially more solid material, so the 70% porosity target can no longer be preserved.

Why the targets can conflict

Porosity and stiffness are not independent sliders. A lattice usually needs more solid material to become stiffer, which leaves less empty space. Change the request to:

Keep at least 70% porosity and at least 20% of the bulk material stiffness.

The tool reports Tradeoff Required instead of pretending both goals were achieved. That warning provides an early reason to change the requirements, material, topology, or design before preparing a unit-cell model or build trial.

What the model is doing

The lattice screen uses a topology-specific Gibson–Ashby power-law relation:

E* / Es = CE (ρ* / ρs)nE

It estimates how much solid material each candidate needs to reach the requested relative stiffness. It then checks solid fraction, cell size, and estimated wall thickness against representative LPBF feature limits for the selected material.

These are homogenized estimates for idealized lattices, not guaranteed as-built properties. The primary screening range is a solid volume fraction of 0.15–0.60, followed by calibration to the chosen topology, process, unit-cell FEA, and measured coupons.

Explore the digital artifacts

The article is connected directly to the working beta. Use the visualizer to understand topology and density, or start with normal language and inspect the model interpretation.

3D gyroid lattice playground showing controls and effective-property estimates

Interactive 3D Playground

Explore Gyroid, Schwarz-P, Schwarz-D, Diamond, IWP, Lidinoid, and Neovius surfaces. Change density, cell size, and material while approximate properties update.

Open the live playground →
Describe Your Part page showing a titanium cylinder prompt and interpreted lattice results

Describe Your Part

Enter a plain-English engineering problem, check what the parser understood, and run the relevant geometry, lattice, structural, thermal, or fluid screens.

Try a plain-language example →

Three ways to use the beta

01

Describe

The easiest starting point when you have an engineering question but do not want to write JSON.

 02

Visualize

Explore how TPMS topology, volume fraction, and material affect geometry and screening estimates.

 03

Analyze

Control the JSON inputs directly and inspect complete model outputs, sweeps, and API examples.

Where the tool is useful

Use the beta to:

  • Compare early TPMS and material candidates quickly.
  • Identify incompatible stiffness and porosity targets.
  • Decide which cases deserve higher-fidelity analysis.
  • Start conversations about material, geometry, and manufacturing constraints.
  • Create a reproducible starting point for FEA and coupon testing.

What this does not replace

Do not use these results as final verification for safety-critical parts. The models do not capture as-built defects, anisotropy, residual stress, fatigue, fracture, contact, complex multidimensional heat flow, or resolved flow through lattice passages. Final decisions still require appropriate engineering analysis, process-specific data, testing, and manufacturing validation.

Try the screening workflow

The current release is a public hosted beta with no signup. Start from the example above, then change one target, material, or dimension at a time.

Describe a part Read the plain-language guide