Plant Wilting Simulation

This repository contains the implementation of the simulator for the plant wilting process, as described in the paper A Physically-inspired Approach to the Simulation of Plant Wilting.

• DOI: https://dl.acm.org/doi/10.1145/3610548.3618218
• PDF: http://computationalsciences.org/publications/maggioli-2023-plant-wilting/maggioli-2023-plant-wilting.pdf

The repository is a modification of the Position Based Dynamics solver, and contains as external dependency the water diffusion model, as described in the publication.

Building Instructions

The building process is entirely based on Git and CMake.
The water diffusion model must be build on its own:

	cd extern/pwd-repo
	mkdir build
	cd build
	cmake .. -DBUILD_SAMPLES=OFF -DCMAKE_INSTALL_PREFIX="../.."
	cmake --build . --config release -j
	cmake --install .

This will produce the water diffusion library and will install it in the directory extern/pwd/.

After that, the application can be built safely from the project root directory:

	mkdir build
	cd build
	cmake ..
	cmake --build . --config release

This will produce an executable PlantDemo inside the directory bin.

Running Instructions

The executable PlantDemo can be run without arguments, which will make it load the default plant.
It is possible to specify the plant as the unique extra argument:

	PlantDemo /path/to/plant.txt

Some test plant files can be found in the directory bin/resources/plants/.

Plant File Format

Besides the test plants in the directory bin/resources/plants/, it is possible to define a custom plant.
A file describing a plant is defined according to the following format

verts num_verts
id,tail_x,tail_y,tail_z,radius,on_leaf[,is_fixed]
...
edges num_edges
id1,id2
...

The first line specifies the number of vertices num_verts after the keyword verts. The actual nodes are specified in the following num_verts lines.
In each line, the node ID is specified with id. Each node represents a segment of the plant, discretized as a cylinder. The tail of the node is specified by the coordinated tail_x,tail_y,tail_z, whereas the radius of the cylinder is given by radius.
Each node is supposed to have its head in the same point as the tail of its parent node. The root node is supposed to have its head at the origin 0,0,0. The root node is determined automatically as the node closer to the origin.
The on_leaf value is always either 0 or 1, and determines if the node is part of the venation of a leaf or if its part of a branch.
The valua is_fixed is always either 0 or 1 and it's optional (by default, 0). It determines if that node is kept in place by external supports, and this feature of the simulation can be enabled and disabled at runtime.
The number of edges num_edges is specified after the keyword edges. If the plant is a unique connected component, then num_edges = num_verts - 1.
Each edge is encoded as a couple of node IDs, separated by a comma.