PKR Core documentation

Open the tool from /app/ and either generate a structure from the Structure menu or import an existing one. From there, pick an analysis type such as Conductivity, Diffusion, Elasticity, Permeability, Liquid intrusion, or CO2 adsorption, configure the calculation conditions, and run it. Use the Study menu to sweep a parameter or build a DOE matrix across many structures, and use the Report tab to review charts and summary metrics once a run finishes. Save the current structure at any point as a .pkz project file, or export individual results as CSV, mesh, or image-stack files.

Each analysis type (Conductivity, Diffusion, Elasticity, Permeability, Liquid intrusion, CO2 adsorption) has its own conditions panel where you set the solve direction and, where more than one is offered, the solve method before running. Conductivity has the widest choice: a reduced-order graph network selected by default, a full 3D field solver that captures curved paths through the structure, and a near-instant straight-column estimate. Diffusion and Permeability pair the default graph network with one fast estimate each; Elasticity adds a 3D spring-network approximation but starts on the straight-column estimate; Liquid intrusion and CO2 adsorption run on the graph network only. Results appear alongside the current structure in the analysis workbench, and feed automatically into the Report tab and, when applicable, the Study run history.

.leS is the native voxel structure format, storing a grid header followed by per-voxel material labels. .pkz is the gzipped project archive written by Save project: it carries one structure's voxel grid, its material assignments, and its generation and edit history, so a saved structure reopens exactly as it was. Beyond these two native formats, PKR Core can import .stl and .obj surface meshes, ASCII VTK structured-points volumes (.vtk), image-stack sequences, and headerless 8-bit raw volumes (.raw / .bin, which have no header, so the grid dimensions and voxel size are entered in the tool before import). Exports cover CSV tables, surfaces (.stl, .obj), FEM volume meshes for Abaqus (.inp) and Fluent (.msh), the native .leS voxel structure, voxel fields as .vtk or headerless .raw, image stacks, analysis reports as Markdown or JSON, extracted pore networks and structural graphs as JSON (including an OpenPNM-ready form), and zipped bundles for parametric-study cases and report charts and tables.

Everything in the workspace is also reachable through a REST API, which is the supported entry point for external tools, scripts, and AI agents. The API base URL is https://api.pakericore.app, and business endpoints such as generate, analyze, and workflows/run require an issued token sent as Authorization: Bearer <token>.

Get a token from /app/ under the Settings & API Tokens tab: open the API Token Dashboard and use Issue API Token. The full token value is shown only once, right after issuing it, so copy it somewhere safe before leaving the page.

The complete API contract is published as an OpenAPI specification at https://api.pakericore.app/api/v1/openapi.yaml, served without authentication so it can be fetched directly by tooling. If you are pointing an AI agent at PKR Core, this single line is enough context for it to start calling the API on its own:

Use this OpenAPI specification to call PKR Core: https://api.pakericore.app/api/v1/openapi.yaml

A ready-made request body for the examples below can be pulled from GET /api/v1/examples, which returns a list of named example recipes. The three calls below cover the core workflow: generate a structure, analyze it, and run a multi-step workflow in one request.

curl -X POST https://api.pakericore.app/api/v1/generate \
  -H "Authorization: Bearer $PKR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"recipe": {"generatorType": "foamLike", "grid": {"nx": 64, "ny": 64, "nz": 64, "voxelSizeUm": 1}}}'

curl -X POST https://api.pakericore.app/api/v1/analyze \
  -H "Authorization: Bearer $PKR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"recipe": {"generatorType": "foamLike", "grid": {"nx": 64, "ny": 64, "nz": 64, "voxelSizeUm": 1}}, "backend": "auto"}'

For an AI agent that wants to request several steps in a single call instead of chaining multiple requests, workflows/run accepts a full workflow definition and returns all of its results together:

curl -X POST https://api.pakericore.app/api/v1/workflows/run \
  -H "Authorization: Bearer $PKR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"workflow": {"recipe": {"generatorType": "foamLike", "grid": {"nx": 64, "ny": 64, "nz": 64, "voxelSizeUm": 1}}, "requestedOutputs": ["metrics"]}}'

Errors from any endpoint share the same body shape, so a single handler can parse all of them:

{"error": {"code": "invalid_request", "message": "recipe is required."}}

No GitHub account or repository access is needed to use the API: the base URL, the token flow above, and the OpenAPI specification are everything required to get started.

The AI chat panel in /app/ can set the parameters listed below. Write a request in plain words, or use the label and example value from the tables to be exact. Paths are the structure and analysis setting keys that the chat applies.

Structure parameters

Parameter	Path	Unit	Description	Example
Generator Type	generatorType	—	Primary microstructure generator type.	Generator Type = fiberPacking
NX	nx	voxels	Grid size along the X axis.	NX = 128
NY	ny	voxels	Grid size along the Y axis.	NY = 128
NZ	nz	voxels	Grid size along the Z axis.	NZ = 128
Seed	seed	—	Random seed for reproducible structure generation.	Seed = 33801
Volume Fraction	volumeFraction	%	Target primary phase volume fraction.	Volume Fraction = 12
Overlap Percent	overlapPercent	%	Maximum allowed overlap percentage between features.	Overlap Percent = 5
Voxel Size	voxelSize	µm	Physical size of each voxel edge.	Voxel Size = 1.5
Binder Volume Fraction	binderVolumeFraction	%	Target binder phase volume fraction.	Binder Volume Fraction = 5
Binder Material ID	binderConfig.materialId	—	Material ID assigned to binder phase.	Binder Material ID = 7
Binder Placement	binderConfig.placement	—	Placement mode for binder material (surfaceShell or contactShell).	Binder Placement = contactShell
Binder Shell Thickness	binderConfig.shellThicknessVoxels	voxels	Thickness of binder shell layer in voxels.	Binder Shell Thickness = 2
Binder Coverage Percent	binderConfig.coveragePercent	%	Percentage of eligible binder candidate voxels to cover (1-100).	Binder Coverage Percent = 70
Foam Material ID	foamConfig.materialId	—	Material ID for foam matrix phase.	Foam Material ID = 3
Foam Noise Scale	foamConfig.noiseScaleVoxels	voxels	Noise spatial scale for foam pore structure.	Foam Noise Scale = 8
Foam Smoothing Passes	foamConfig.smoothingPasses	—	Number of smoothing iterations for foam matrix.	Foam Smoothing Passes = 2
Foam Threshold Jitter	foamConfig.thresholdJitter	—	Random jitter amplitude for foam density threshold.	Foam Threshold Jitter = 0.12
Layer Axis	layerConfig.axis	—	Stacking direction axis (x, y, or z) for layered structure.	Layer Axis = z
Layers List	layerConfig.layers	—	List of layer definitions with material, thickness fraction, and roughness.	Layers List = [{"materialId":1,"thicknessFraction":0.5,"roughness":0},{"materialId":2,"thicknessFraction":0.5,"roughness":0}]
Warp Material ID	wovenFiberConfig.warpMaterialId	—	Material ID for warp yarns.	Warp Material ID = 1
Weft Material ID	wovenFiberConfig.weftMaterialId	—	Material ID for weft yarns.	Weft Material ID = 2
Yarn Radius	wovenFiberConfig.yarnRadius	voxels	Yarn cross-section radius in voxels.	Yarn Radius = 3
Warp Spacing	wovenFiberConfig.warpSpacing	voxels	Center-to-center spacing between warp yarns.	Warp Spacing = 10
Weft Spacing	wovenFiberConfig.weftSpacing	voxels	Center-to-center spacing between weft yarns.	Weft Spacing = 10
Layer Count	wovenFiberConfig.layerCount	—	Number of stacked woven fabric layers.	Layer Count = 2
Filler Configs List	fillerConfigs	—	List of particle or fiber filler specifications. Fiber entries also accept wavinessAmplitudeVoxels (0-16) and wavinessPeriodVoxels (4-256) for sinusoidal curved fibers.	Filler Configs List = [{"type":"fiber","radius":2,"volumeFraction":10,"materialId":1,"wavinessAmplitudeVoxels":3,"wavinessPeriodVoxels":12}]

Analysis parameters

Parameter	Path	Unit	Description	Example
Conductivity Direction	conductivityDirection	—	Transport axis for effective conductivity.	Conductivity Direction = z
Conductivity Method	conductivityMethod	—	Computation method: 3d = full field, graph-network = graph proxy, simple = column average.	Conductivity Method = 3d
Diffusion Direction	diffusionDirection	—	Transport axis for effective diffusion.	Diffusion Direction = z
Diffusion Method	diffusionMethod	—	Computation method: effective-medium or others available in the dropdown.	Diffusion Method = effective-medium
Diffusion Approximation Method	diffusionApproximationMethod	—	Reduced-order model used when Diffusion Method is graph-network: skeleton-graph = skeleton graph, canonical-pore = PKR canonical pore network.	Diffusion Approximation Method = canonical-pore
Permeability Direction	permeabilityDirection	—	Transport axis for permeability.	Permeability Direction = z
Permeability Method	permeabilityMethod	—	Computation method: pore-network = connectivity estimate, graph-network = reduced-order graph solve.	Permeability Method = graph-network
Permeability Max Pressure Drop	permeabilityPressureMax	Pa	Maximum pressure drop used for the permeability pressure-flow curve sweep.	Permeability Max Pressure Drop = 1000
Permeability Curve Steps	permeabilityFlowStepCount	—	Number of pressure steps sampled for the permeability pressure-flow curve.	Permeability Curve Steps = 5
Elasticity Direction	elasticityDirection	—	Load axis for effective Young's modulus.	Elasticity Direction = z
Elasticity Method	elasticityMethod	—	Computation method: voxel-spring-network (column estimate), 3d-scalar-spring-network (3D spring network), or graph-network (reduced-order stiffness proxy).	Elasticity Method = voxel-spring-network
Elasticity Loading Mode	elasticityLoadingMode	—	Loading direction of the elasticity strain sweep (tension or compression).	Elasticity Loading Mode = compression
Elasticity Min Strain	elasticityStrainMin	%	Minimum strain magnitude (percent) for the elasticity strain sweep.	Elasticity Min Strain = 0
Elasticity Max Strain	elasticityStrainMax	%	Maximum strain magnitude (percent) for the elasticity strain sweep.	Elasticity Max Strain = 5
Elasticity Sweep Steps	elasticityStepCount	—	Number of strain steps sampled for the elasticity strain sweep.	Elasticity Sweep Steps = 10
Liquid Intrusion Direction	invasionDirection	—	Intrusion axis for liquid intrusion (invasion percolation).	Liquid Intrusion Direction = z
CO2 Adsorption Direction	co2Direction	—	Flow direction for the CO2 adsorption breakthrough analysis.	CO2 Adsorption Direction = z
Liquid Intrusion Surface Tension	invasionSurfaceTension	N/m	Surface tension used by the liquid intrusion capillary pressure model.	Liquid Intrusion Surface Tension = 0.072
Liquid Intrusion Contact Angle	invasionContactAngle	deg	Contact angle used by the liquid intrusion capillary pressure model.	Liquid Intrusion Contact Angle = 140
CO2 Isotherm Model	co2IsothermModel	—	Adsorption isotherm model used for the CO2 adsorption breakthrough analysis.	CO2 Isotherm Model = toth
CO2 Velocity	co2Velocity	m/s	Interstitial flow velocity for the CO2 adsorption breakthrough analysis.	CO2 Velocity = 0.02
CO2 Diffusivity	co2Diffusivity	m^2/s	Molecular diffusivity for the CO2 adsorption breakthrough analysis.	CO2 Diffusivity = 1.6e-5
CO2 Adsorbent Density	co2AdsorbentDensity	kg/m³	Bulk density of the adsorbent phase used for CO2 loading.	CO2 Adsorbent Density = 1200
CO2 Maximum Loading qMax	co2QMax	mol/kg	Saturation loading of the adsorption isotherm.	CO2 Maximum Loading qMax = 5
CO2 Affinity Constant b	co2BPerPa	1/Pa	Isotherm affinity constant for the Langmuir/Toth model.	CO2 Affinity Constant b = 2e-5
CO2 Toth Exponent	co2TothExponent	—	Toth isotherm exponent; only used when the isotherm model is toth.	CO2 Toth Exponent = 0.7
CO2 Simulation Time	co2SimulationTime	s	Total simulated time for the CO2 adsorption breakthrough run.	CO2 Simulation Time = 200
CO2 Time Step	co2TimeStep	s	Time increment used by the CO2 adsorption breakthrough integration.	CO2 Time Step = 0.05
CO2 LDF Rate Constant	co2KLdf	1/s	Linear driving force mass transfer rate constant for CO2 uptake.	CO2 LDF Rate Constant = 0.5
Seed Merge Factor	poreNetworkSeedMergeFactor	—	Seed merge factor used when extracting the pore network from the distance transform maxima.	Seed Merge Factor = 1.5