FEMNET trawl net visualiser — built on Three.js r165

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Input Files

.mdg — FEMNET mesh description file (produced by phobos). Contains node coordinates (X,Y,Z), cable/bar elements, and netting surface triangles with per-vertex U,V mesh coordinates.

.sta — Static solution file (produced by 4c19 solver). Block 1: equilibrium node positions. Block 2: convergence data (one value per element). Block 3: per-surface tension/strain data (two 3-component vectors per triangle). Units of Block 3 are not confirmed by documentation — values are displayed as raw numbers.

.des — Optional descriptor file giving panel-type names. Used to label the per-panel colour overlay.

Load files via File → Open .mdg / .sta / .des…. The last loaded net and all settings are remembered automatically between sessions.

Menu Overview

View Net — Groups

Display — Groups

Tension / Strain Overlay

When a .sta file is loaded, per-surface values from Block 3 are available as a colour overlay on the netting panels. Values are node-averaged for smooth colour gradients.

Colour maps: Spectrum (blue→red), Spectrum with 10% contour lines, Stepped (9 bands), Black→White, and an Invert toggle.

LUT controls: The colourbar shows the active spectrum. Drag the lower triangle handles to set the LUT min and max. The upper grey markers show the data min/max. The ←/→ step buttons shift the entire LUT window by the entered step size.

Interrogator: Toggle “Interrogate tension (click net)” then click any panel to read the interpolated tension value at that point. Only the near layer is reported. Black + crosshair markers appear at the hit point and its mirror, and clear when interrogation is toggled off.

U/V Twines

Diamond-mesh netting has two families of twines running diagonally. Each FE triangle carries per-vertex U,V mesh coordinates. The viewer draws lines of constant U+V (orange) and constant U−V (green) across each triangle surface. The twine period slider controls how many mesh rows apart each visible twine line is.

Node Type Overlay

Colours node spheres by their type code from the .mdg file. Named types: fixed (1), free (2), constrained (3). Hovering over a node sphere on either side of the net shows its index and position (X, lateral, depth) when a .sta file is loaded. Clicking a node places a coloured circle ring marker at that node. Use Highlight type to isolate nodes of a specific type number.

Collapse State & Defaults

All collapsible groups remember their open/closed state between sessions. If you collapse a group, it stays collapsed on the next load until you expand it again.

All slider and toggle states are saved automatically to browser storage on every change and restored on the next page load, along with the last loaded net. Use Display → Save current settings as defaults to explicitly capture the current state as the startup default. Use Reset in the View Net top bar to clear saved settings and reload the built-in defaults.

Install as App

On Chrome or Edge (desktop/Android), File → Add program to desktop installs Borstad NetView as a standalone app with its own window and taskbar/dock icon. On iOS Safari, File → Add program to menu bar shows instructions to add it to the home screen. Both options are only shown when the page is served over HTTPS.

About

Borstad NetView was built to replicate and extend the visualisation capabilities of the original FEMNET batz tool (D. Priour, IFREMER). It is a self-contained single-file HTML application requiring no installation — open in any modern browser.

Built with Three.js r165  •  FEMNET file formats by D. Priour, IFREMER  •  Viewer Design by G Borstad