Shape Modeling of Plant Leaves with Unstructured Meshes

The plant leaf is one of the most challenging natural objects to be realistically depicted by computer graphics due to its complex morphological and optical characteristics. Although many studies have been done on plant modeling, previous research on leaf modeling required for close-up realistic plant images is very rare. In this thesis, a novel method for modeling of the leaf shape based on the leaf venation is presented. As the first step of the method, the leaf domain is defined by the enclosure of the leaf boundary. Second, the leaf venation is interactively modeled as a hierarchical skeleton based on the actual leaf image. Third, the leaf domain is triangulated with the skeleton as constraints. The skeleton is articulated with nodes on the skeleton. Fourth, the skeleton is interactively transformed to a specific shape. A user can manipulate the skeleton using two methods which are complementary to each other: one controls individual joints on the skeleton while the other controls the skeleton through an intermediate spline curve. Finally, the leaf blade shape is deformed to conform to the skeleton by interpolation. An interactive modeler was developed to help a user to model a leaf shape interactively and several leaves were modeled by the interactive modeler. The ray-traced rendering images demonstrate that the proposed method is effective in the leaf shape modeling

Branching Boogaloo: Botanical Adventures in Multi-Mediated Morphologies

FormaLeaf is a software interface for exploring leaf morphology using parallel string rewriting grammars called L-systems. Scanned images of dicotyledonous angiosperm leaves removed from plants around Bard’s campus are displayed on the left and analyzed using the computer vision library OpenCV. Morphometrical information and terminological labels are reported in a side-panel. “Slider mode” allows the user to control the structural template and growth parameters of the generated L-system leaf displayed on the right. “Vision mode” shows the input and generated leaves as the computer ‘sees’ them. “Search mode” attempts to automatically produce a formally defined graphical representation of the input by evaluating the visual similarity of a generated pool of candidate leaves. The system seeks to derive a possible internal structural configuration for venation based purely off a visual analysis of external shape. The iterations of the generated L-system leaves when viewed in succession appear as a hypothetical development sequence. FormaLeaf was written in Processing

Space colonisation based procedural road generation

Dissertação de mestrado em Computer ScienceProcedural generation of content has been studied for quite some time and it is increasingly relevant in scientific areas and in video-game and film industries. Procedural road layout generation has been traditionally approached using L-Systems, with some works exploring alternative avenues. Although originally conceived for biological systems modelling, the adequacy of L-Systems as a base for road generation has been demonstrated in several works. In this context, this work presents an alternative approach for procedural road layout generation that is also inspired by plant generation algorithms: space colonisation. In particular, this work uses the concept of attraction points introduced in space colonisation as its base to produce road layouts, both in urban and inter-city environments. As will be shown, the usage of attraction points provides an intuitive way to parameterise a road layout. The original Space Colonization Algorithm (SCA) generates a tree like structure, but in this work, the extensions made aim to fully generate a inter-connected road network. As most previous methods the method has two phases. A first phase generates what is mostly a tree structure growing from user defined road segments. The second phase performs the inter connectivity among the roads created in the first phase. The original SCA parameters such as the killradius help to control the capillarity of the road layout, the number of attraction points used by each segment will dictate its relevance establishing a road hierarchy naturally dependent on the distribution of the attraction points on the terrain. An angle control allows the creation of grid like or more organic road layouts. The distribution of the attraction points in the terrain can be conditioned by boundary maps, containing parks, sea, rivers, and other forbidden areas. Population density maps can be used to supply an explicit probabilistic distribution to the attraction points. Flow-fields can be used to dictate the flow of the road layout. Elevation maps provide an additional restriction regarding the steepness of the roads. The tests were executed within a graphic toolbox developed simultaneously. The results are exported to a geographical information file format, GeoJSON, and then maps are rendered using a geospatial visualisation and processing framework called Mapnik. For the most part, parameter settings were intuitively reflected on the road layout and this method can be seen as a first step towards fully exploring the usage of attraction points in the context of road layout.Gradualmente a geração procedimental de conteúdo tem-se tornado cada vez mais relevante, sendo maioritariamente aplicada em industrias como a dos vídeo-jogos e cinema. No que toca à geração procedimental de redes de estradas, grande parte das abordagens em torno deste tema são baseadas em L-Systems. Embora a área de aplicação dos L-Systems tenha sido originalmente para produzir modelos de sistemas biológicos, mostrou também ser um algoritmo adequado para a geração procedimental de redes de estradas. Este trabalho apresenta uma abordagem alternativa à geração procedimental de redes de estradas que também é inspirada num algoritmo procedimental de geração de plantas, colonização espacial, utilizando o conceito de pontos de atracão como base para gerar padrões de estradas. Como será demonstrado, a utilização de pontos de atracão fornece uma maneira intuitiva de parametrizar um padrão de estradas desejado. Como a maioria dos trabalhos feitos nesta área, este método tem duas fases. A primeira fase gera uma rede semelhante a uma árvore criada a partir de um ou mais segmentos iniciais da rede determinados pelo utilizador. A segunda fase trata de interligar as estradas geradas na primeira fase. Os parâmetros iniciais do algoritmo de colonização espacial, como o kill radius, ajudam a controlar a capilaridade da rede, os pontos de atracão que influenciam cada segmento irão ditar a sua relevância na rede geral, estabelecendo a noção de hierarquia de estradas, dependendo da distribuição de pontos de atracão no terreno. O controlo do ângulo entre segmentos permite a criação de padrões de estradas tanto em forma de grelha como padrões mais orgânicos. A distribuição dos pontos de atracão no terreno pode ser influenciada por mapas de fronteira, que contem as áreas válidas e/ou inválidas, como parques, mar, rios, e outras áreas proibidas. Mapas de densidade populacional podem ser usados para fornecer uma distribuição probabilística dos pontos de atracão. Campos de forças, podem ser usados para ditar o fluxo da rede de estradas. Mapas de elevação oferecem uma restrição adicional tendo em conta a inclinação das estradas. De um modo geral, as definições de parâmetros refletiram-se de um modo intuitivo nos padrões de redes de estradas gerados, e este trabalho pode ser considerado como um primeiro passo na exploração do conceito de pontos de atracão na área da geração de redes de estradas

Venation Skeleton-Based Modeling Plant Leaf Wilting

A venation skeleton-driven method for modeling and animating plant leaf wilting is presented. The proposed method includes five principal processes. Firstly, a three-dimensional leaf skeleton is constructed from a leaf image, and the leaf skeleton is further used to generate a detailed mesh for the leaf surface. Then a venation skeleton is generated interactively from the leaf skeleton. Each vein in the venation skeleton consists of a segmented vertices string. Thirdly, each vertex in the leaf mesh is banded to the nearest vertex in the venation skeleton. We then deform the venation skeleton by controlling the movement of each vertex in the venation skeleton by rotating it around a fixed vector. Finally, the leaf mesh is mapped to the deformed venation skeleton, as such the deformation of the mesh follows the deformation of the venation skeleton. The proposed techniques have been applied to simulate plant leaf surface deformation resulted from biological responses of plant wilting

Procedural Modeling and Constrained Morphing of Leaves

Ph.DDOCTOR OF PHILOSOPH

A constructive approach for the generation of underwater environments

This paper introduces Coralize, a library of generators for marine organisms such as corals and sponges. Using constructive algorithms, Coralize can generate stony corals via L-system grammars, soft corals via leaf venation algorithms and sponges via nutrient-based mesh growth. The generative algorithms are parameterizable, allowing a user to adjust the parameters in order to create visually appealing 3D meshes. Such meshes can be used to automatically populate a seabed or reef, in order to create a biologically realistic and aesthetically pleasing underwater environment.The research was supported, in part, by the FP7 ICT projects C2Learn (project no: 318480) and ILearnRW (project no: 318803), and by the FP7 Marie Curie CIG project AutoGameDesign (project no: 630665).peer-reviewe