Blender Plugin for Conversion of Models to Vector Graphic

Tato práce řeší návrh a implementaci rozšíření (pluginu) pro software Blender. Toto rozšíření přidává funkcionalitu převodu 3D modelů ve scéně Blenderu na soubor 2D vektorové grafiky ve formátu SVG tak, aby tento soubor reprezentoval původní scénu. Práce se zabývá tvorbou uživatelského rozhraní pluginu, převodem souřadnic vrcholů modelů ze 3D souřadnic scény na 2D souřadnice okna, výpočtem barvy výsledných polygonů na základě osvětlení a barvy materiálu, řezáním konfliktních (zaklíněných) objektů a určováním pořadí, v jakém je třeba výsledné polygony vykreslit. Výsledkem implementace je plugin, který umožňuje uživateli namísto ruční tvorby 2D vektorových obrázků vytvářet 3D modely, které lze následně ze scény Blenderu převádět (fotit) do souborů vektorové grafiky ve formátu SVG.This thesis deals with the design and implementation of an extension (plugin) for Blender software. This extensions adds the feature of converting 3D models in a Blender scene to a 2D vector graphics file in the SVG format that represents the original scene. The thesis focuses on creating the plugin's user interface, conversion of vertex coordinates from 3D scene to 2D window coordinates, calculating the resulting polygon color based on lighting and material, cutting of conflicting (colliding) objects and determining the order in which the resulting polygons have to be drawn. The result of the implementation is a plugin that allows the user to create 3D models which can be converted (snapshot) to SVG formatted vector graphics files, instead of manually creating 2D vector images.

Lake water acidification and temperature have a lagged effect on the population dynamics of Isoëtes echinospora via offspring recruitment

The aquatic quillwort, Isoëtes echinospora, survived the strong water acidification during 1960s–1990s in Plešné Lake (Bohemian Forest, Central Europe), but failed to reproduce. We studied the relationships between a recent population recovery and an improvement of lake water quality. We used correlation analysis to evaluate lagged seasonal effects of lake water quality on population dynamics during the past decade, and factor analysis to determine the independent factors responsible for population recovery. We also provided a water-quality-based reconstruction of population growth from the beginning of the lake recovery two decades ago, using a partial least squares regression (PLSR) model of population growth. We identified three independent controlling factors: nutrients (nitrate, phosphorus, calcium, potassium, magnesium), stressors (pH, ionic aluminium) and temperature. Of these, nutrient availability did not limit the quillwort growth, but annual mean pH and winter mean concentrations of toxic ionic aluminium influenced population growth through negative effects on sporeling establishment until the age of one year, while cumulative temperature in spring and summer controlled the later plant growth. Thus, water quality in the acidified Plešné Lake mainly controls recruitment success rather than adult survival of Isoëtes echinospora. This study provides the first in situ evidence that the recruitment success, namely the annual increment in the adult quillwort population, indicates the degree of recovery from acidification, however further extensive investigation is required to more accurately quantify, and therefore understand, the relationships between recruitment, water quality and other factors