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.

Effects of bark beetle disturbance on soil nutrient retention and lake chemistry in glacial catchment

Forest ecosystems worldwide are subjected to human-induced stressors, including eutrophication and acidification, and to natural disturbances (for example, insect infestation, windstorms, fires). The occurrence of the later is expected to increase due to the ongoing climate change. These multi-stressor forcings modify ecosystem biogeochemistry, including the retention of limiting nutrients, with implications for terrestrial and aquatic biodiversity. Here we present whole ecosystem nutrient (N, Ca, Mg, K) mass balances in the forested catchment of Plešné Lake, CZ, which has undergone transient changes linked to the recovery from anthropogenic acidification and to the forest disturbances caused by severe infestations by the bark beetle (Ips typographus). Measured fluxes and storage of nutrients in the lake-catchment ecosystem were used to constrain the processoriented biogeochemical model MAGIC (Model of Acidification of Groundwater In Catchments). Simulated lake water chemistry and changes in soil nutrient pools fitted observed data and revealed that (1) the ecosystem N retention declined, thus nitrate leaching increased for 10 years following the bark beetle disturbance, with transient adverse effects on the acid–base status of lake water, (2) the kinetics of nutrient mineralisation from decaying biomass coupled with nutrient immobilisation in regrowing vegetation constrained the magnitude and duration of ecosystem losses of N, Ca and Mg, (3) the excess of mineralised base cations from decomposing biomass replenished the soil cation exchange matrix, which led to increased soil base saturation, and (4) the improvement of the catchment soil acid–base status led to an increase of lake water pH and acid neutralising capacity. Forested ecosystems underlain by nutrient-poor soils and bedrock are prone to human-induced damages caused by acidification and eutrophication, and any natural disturbance may further lead to nutrient imbalances. We demonstrated that in this natural forest ecosystem protected from human intervention, disturbances together with natural post-disturbance vegetation recovery have temporally positive effects on the nutrient stores in the soil