Screening a TPMS Lattice Tradeoff Before FEA | 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<br>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.
No signup
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.
Deterministic phrase parser → geometry and lattice screening<br>Run screening
Open the complete result and other examples →
Interactive artifact: change topology, density, and material
In this article
What this is<br>Start without code<br>Why targets conflict<br>What the model does<br>Explore the artifacts<br>Where it is useful<br>Model scope
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.<br>Copy
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.<br>Copy
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.
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
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<br>Describe
The easiest starting point when you have an engineering question but do not want to write JSON.
02<br>Visualize
Explore how TPMS topology, volume fraction, and material affect...