Because all fuel items (Plant and LayerSet) are converted in FuelMatrix of small voxels before being interpolated on Firetec grid, this export can be long to very long depending on the tree number. Use the script mode in case of large scene with numerous trees.

• Pick a directory for output files:

• This will launch the main Exporter interface:

1. Select the first grid file and the number of grid files if several (for parallel computations)
2. load it (them) 1. Load grid files
3. Eventually adjust WFDS parameter
4. Hit 2. load WFDS parameters
5. Eventually adjust Exporter parameters (see below)
6. Hit 3. Export fuel items (main action)
7. Eventually modify the name of your WFDS input files
8. Hit 4. Save files

Among the options available for the Exporter:

• Plant discretisation ratio is a real between 0 and 1 that determines the size of the FuelMatrix voxels as a fraction of the plant extension in 3D. The default it 0.1, so that a plant will be decomposed in 1000 voxels.
• LayerSet discretization dx is the horizontal size of the FuelMatrix voxels used to decompose the LayerSet. If the LayerSet is homogeneous and/or the WFDS cell are large, there is no need to take a small value.
• LayerSet discretization ratio is similar to plant discretization ratio for the layerSet height. A minimal value of LayerSet discretization minimum dz can be prescribed to avoid over resolution of a litter layer for example (when shrub LayerSet are present at the same time).
• Voxel number for layerset cutting is the maximum number of voxel allowed for the discretization of LayerSets. If a LayerSet decomposition requires a larger number of voxels, it will be triangulated recursively in pieces until all pieces required less voxels that the number prescribed. If the export leads to memory problem, either increase memory allocated to capsis or decrease this number.
• Crown overlapping allows all crown to overlap, so that fuels of several trees at the some locations can sometimes lead to unrealistically high local bulk densities. To avoid this, when crown overlapping is not selected (default), the biomass within the WFDS voxel will be limited to the maximum bulk volume of the voxel. In other words, it is not possible to put a larger fuel volume in this cell than the cell volume.
• Production of tree crown voxel list provides an additional output of the export which is the list of WFDS voxels associated to each individual Plant and LayerSet. This is useful for ecological applications such as computing fire effect or fluxes to a given Item.
• Select the particle you want to export to WFDS. Select all and Unselect all are useful to limit the click numbers.