Modern graphics accelerators have embedded programmable components in the form of vertex and fragment shading units. Current APIs permit specification of the programs for these components using an assembly-language level interface. Compilers for high-level shading languages are available but these read in an external string specification, which can be inconvenient. It is possible, using standard C++, to define an embedded high-level shading language. Such a language can be nearly indistinguishable from a special-purpose shading language, yet permits more direct interaction with the specification of textures and parameters, simplifies implementation, and enables on-the-fly generation, manipulation, and specification of shader programs. An embedded shading language also permits the lifting of C++ host language type, modularity, and scoping constructs into the shading language without any additional implementation effort.

Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-10Bitstream added on 2014-06-13T20:22:26Z : No. of bitstreams: 1 ayres_mcr_dr_botfca.pdf: 1999593 bytes, checksum: 4eed8f4e59e415e484ad679e07a8b14b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O objetivo desta pesquisa foi o estudo de diferentes espécies arbóreas quanto ao sombreamento e seus efeitos na temperatura de um ambiente construído, a partir de medições de temperaturas de globo e do ar, umidade relativa e velocidade do vento. A pesquisa foi desenvolvida na Empresa Brasileira de Pesquisa Agropecuária/Embrapa Agropecuária Oeste, no município de Dourados-MS. Foram analisados o sombreamento de duas espécies arbóreas, a Sibipiruna (Caelsalpinia peltophoroides) e o Flamboyant (Delonix regia), quanto à atenuação da temperatura em ambientes internos, proporcionada pela sombra de cada uma das espécies, em edificações abertas. Os dados foram coletados em dois módulos de edificação de madeira e cobertos com telhas de fibro-cimento, localizados ao sol e à sombra das espécies analisadas. Nestes módulos foram obtidos dados de temperatura do ar, umidade relativa e temperatura de globo negro. Os dados de velocidade do vento foram obtidos na Estação Meteorológica da Embrapa Agropecuária Oeste. Com os dados obtidos foram calculadas as porcentagens de atenuação da temperatura para cada um dos módulos e as variações relativas das temperaturas do ar e de globo negro. Avaliando-se os resultados obtidos, observou-se que o sombreamento natural produzido pela Sibipiruna proporcionou à sombra uma atenuação na temperatura de globo negro de 2,82ºC e na temperatura do ar de 0,96ºC menor em relação aos dados obtidos ao sol e, uma porcentagem de atenuação de 8.34 % e 3,16% respectivamente. Analisando-se os resultados, observou-se que o sombreamento natural do Flamboyant produziu à sombra uma atenuação na temperatura de globo negro de 3,96ºC e na temperatura do ar de 1,26ºC menor em relação aos dados obtidos ao sol e, uma porcentagem de atenuação de 9.62% e 3,46% respectivamente... / The objective of this research was to study different arboreal species in relation to the shading and its effects on temperature of a constructed environment, from measurements of temperatures of the globe and of the air, relative humidity and speed of the wind. The research was developed at Brazilian company of farming research/Embrapa Agropecuária Oeste, on Dourados City, Mato Grosso do Sul State. The shading of two arboreal species, Sibipiruna tree (Caelsalpinia peltophoroides) and Flamboyant tree (Delonix regia) had been analyzed in relation to the attenuation of the temperature in internal environments, provided for the shade of each one of the species, in opened constructions. The data had been collected in two modules of wooden construction and covered with asbestos-cement roofing tiles, located under the sun and in the shade of the analyzed species. In these modules, they had been gotten data of temperature of the air, relative humidity and temperature of the black globe. The data of speed of the wind had been gotten at Meteorological Station from Embrapa Agropecuária Oeste. With the gotten data, the percentages of attenuation of the temperature for each one of the modules and the relative variations of the temperatures of the air and of the black globe had been calculated. Evaluating the results gotten, it is observed that the natural shading produced by Sibipiruna tree provided to the shade an attenuation on temperature of the black globe of 2.82ºC and on temperature of the air of 0.96ºC lesser than the data gotten under the sun, and a percentage of attenuation of 8.34 % and 3.16%, respectively. Analyzing the results, it is observed that the natural shading of Flamboyant tree produced to the shade an attenuation on temperature of the black globe of 3.96ºC and...(Complete abstract, click electronic access below)

Resumo: O objetivo desta pesquisa foi o estudo de diferentes espécies arbóreas quanto ao sombreamento e seus efeitos na temperatura de um ambiente construído, a partir de medições de temperaturas de globo e do ar, umidade relativa e velocidade do vento. A pesquisa foi desenvolvida na Empresa Brasileira de Pesquisa Agropecuária/Embrapa Agropecuária Oeste, no município de Dourados-MS. Foram analisados o sombreamento de duas espécies arbóreas, a Sibipiruna (Caelsalpinia peltophoroides) e o Flamboyant (Delonix regia), quanto à atenuação da temperatura em ambientes internos, proporcionada pela sombra de cada uma das espécies, em edificações abertas. Os dados foram coletados em dois módulos de edificação de madeira e cobertos com telhas de fibro-cimento, localizados ao sol e à sombra das espécies analisadas. Nestes módulos foram obtidos dados de temperatura do ar, umidade relativa e temperatura de globo negro. Os dados de velocidade do vento foram obtidos na Estação Meteorológica da Embrapa Agropecuária Oeste. Com os dados obtidos foram calculadas as porcentagens de atenuação da temperatura para cada um dos módulos e as variações relativas das temperaturas do ar e de globo negro. Avaliando-se os resultados obtidos, observou-se que o sombreamento natural produzido pela Sibipiruna proporcionou à sombra uma atenuação na temperatura de globo negro de 2,82ºC e na temperatura do ar de 0,96ºC menor em relação aos dados obtidos ao sol e, uma porcentagem de atenuação de 8.34 % e 3,16% respectivamente. Analisando-se os resultados, observou-se que o sombreamento natural do Flamboyant produziu à sombra uma atenuação na temperatura de globo negro de 3,96ºC e na temperatura do ar de 1,26ºC menor em relação aos dados obtidos ao sol e, uma porcentagem de atenuação de 9.62% e 3,46% respectivamente...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this research was to study different arboreal species in relation to the shading and its effects on temperature of a constructed environment, from measurements of temperatures of the globe and of the air, relative humidity and speed of the wind. The research was developed at Brazilian company of farming research/Embrapa Agropecuária Oeste, on Dourados City, Mato Grosso do Sul State. The shading of two arboreal species, Sibipiruna tree (Caelsalpinia peltophoroides) and Flamboyant tree (Delonix regia) had been analyzed in relation to the attenuation of the temperature in internal environments, provided for the shade of each one of the species, in opened constructions. The data had been collected in two modules of wooden construction and covered with asbestos-cement roofing tiles, located under the sun and in the shade of the analyzed species. In these modules, they had been gotten data of temperature of the air, relative humidity and temperature of the black globe. The data of speed of the wind had been gotten at Meteorological Station from Embrapa Agropecuária Oeste. With the gotten data, the percentages of attenuation of the temperature for each one of the modules and the relative variations of the temperatures of the air and of the black globe had been calculated. Evaluating the results gotten, it is observed that the natural shading produced by Sibipiruna tree provided to the shade an attenuation on temperature of the black globe of 2.82ºC and on temperature of the air of 0.96ºC lesser than the data gotten under the sun, and a percentage of attenuation of 8.34 % and 3.16%, respectively. Analyzing the results, it is observed that the natural shading of Flamboyant tree produced to the shade an attenuation on temperature of the black globe of 3.96ºC and...(Complete abstract, click electronic access below) / Orientador: Luiz Antonio Targa / Coorientador: Paula Pinheiro Padovese Peixoto / Banca: Marco Antonio M. Biaggioni / Banca: Maria de Lourdes Conte / Banca: Manoel Carlos Gonçalves / Francisco Jose Blasi de T. Piza / Doutor

Background- Autodesk Maya is by its long existence one of the most established 3D-modeling software that enables users to create meshes and the software can handle a majority of processes associated with graphic models, animation, and rendering. Although there are arguably different third-party plug-ins that can be used to enhance the efficiency of Maya. Maya’s own built-in rendering functions, especially its real-time rendering engine feel less efficient than other available real-time rendering options, which additionally commonly provide different rendering techniques that can be used to give a desired style to the modeled scene.  Objectives- Maya in its built-in rendering engines themselves does not offer much in terms of non-realistic rendering techniques; therefore, rendering in, for example, Toon-shading requires more work and effort. The objective is to implement a prototype plug-in to that can do real-time rendering of a realistic as well as non-photorealistic rendering technique inside of Autodesk Maya 2023. Its future aim is to address the non-effective and time-consuming task of viewing the results of light adjustments and setting the scene up for stylized renders in Maya.  Methods- Through the method of implementation, a basic plug-in to Autodesk Maya was constructed in Visual Studio using C++ and DirectX 11 library. It employs Qt-window to render the Maya scene in real-time and, additionally, has the function of Toon-shading. The prototype plug-in is then put through a simple test using manual assessment. The prototype’s visual rendered output, rendering times, processing usage, and memory usage are presented and compared to the results from Maya 2023’s built-in rendering options when rendering a constructed test-scene to find out where the plug-in requires further adjustments to its implementation. Results- The results show that a real-time plug-in with the additional function of Toon-shading was implementedusing the defined method of implementation. From the later test, the prototype’s rendered results arepresented and compared to the results of Autodesk Maya 2023’s built-in rendering options when rendering the constructed test-scene. Conclusion- The prototype by collecting information from the Maya scene and running the same data through the DirectX pipeline allows for different rendering styles to be developed and displayed through the user-friendly graphical user interface developed with the Qt-library. With the press of a button different implemented rendering styles like the one of Toon-shading can be applied to the prototype’s window display of the Maya scene. Its real-time rendering allows the user to see the implemented graphical attributes done to the scene without time delay. Which makes the job of finding the right angle for the intended render more efficient. The intended rendered scene can then easily be saved by the press of another button. The time and workflow no longer require the 3D-model to be imported to another rendering software or to apply different materials to all parts of the different Maya 3D-models when trying to achieve a non-photorealistic rendering style. The implemented prototype is very basic, andmore implementation is required before the prototype can be used as an efficient rendering alternative for stylized rendering in Maya.

Background. The game-industry is rapidly demanding more and more comput-ing power in its strive for more realistic renditions of environments, simulations andgraphics. To accelerate the improvements made to the realism of real time graph-ics further, optimizations like Clustered and Cascaded Clustered Shading come intoplay. The purpose of these techniques is to reduce the time it takes to render aframe by dividing the view frustum into smaller segments called clusters that canthen be used for light calculations. Cascaded Clustered Shading is a slightly morecustomizable method which aims to improve on Clustered Shading by allowing morecontrol over how the view frustum is divided into clusters. Objectives. The goal of our thesis is to explore the effectiveness of Cascaded Clus-tered Shading compared to Clustered Shading in a scene with 64, 256, 1024 and 4096lights respectively. It is also to find the trend of what type of subdivision pattern thatperforms best in what situation. Thus proving or disproving the theory that moreuniform cluster sizes are beneficial in reducing the complexity of light calculations incomparison to the increasing cluster sizes present in Clustered Shading. Methods. To answer these questions we implemented the techniques in a test scenewhere we could easily compare the performance of the different subdivision patternsand techniques with 64, 256, 1024 and 4096 lights respectively. Three different pat-terns were tested, one with an increasing number of subdivisions per layer P1 (anincrease in the number of clusters per layer). One with a static number of subdi-visions per layer P2, representing the performance of Clustered Shading. One witha decreasing number of subdivisions per layer P3. Additional performance metricsto be recorded were added, measuring the time it took for the different parts of thetechnique so that not just the general performance could be compared. Thus themethod used was a quantitative research method of implementation and experimen-tation. Results. The results supports the theory that more uniform cluster sizes tend tobe beneficial when rendering a scene with many lights showing a clear trend to favora pattern creating more uniform clusters P1. However the results also show a con-tradicting overall performance increase (comparing FPS) using the reversed patternwith sharply increasing cluster sizes based on the distance from the camera P3. Theoverall performance of pattern P1 and P3 was better than P2. Conclusions. The conclusions drawn from the results are that Cascaded ClusteredShading perform better than Clustered Shading in most cases depending on the pat-tern, and that more uniform cluster sizes are beneficial when rendering many lightsin most cases.

Recently there was a significant grow in building HPC systems. Nowadays they are building from mainstream computer components. One of them is graphics accelerators with GPU. This thesis deals with description of graphics accelerators. It examines possibilities usage. GPU chip has hundreds simple processors. This thesis examine possibilities how to benefit from these parallel processors. It contains description of several testing applications, discuss results from experiments and compares them with another components used for HPC.

O objetivo deste trabalho foi avaliar a influência de ambientes cobertos com filme de polietileno branco leitoso e diferentes malhas de sombreamento (Termo-refletora -50% e Preta - 50%) nas seguintes variáveis ambientais: irradiância solar global, irradiância fotossinteticamente ativa, temperatura e umidade relativa do ar e evapotranspiração, e de seus respectivos microclimas no crescimento, no desenvolvimento e na qualidade da Gerbera jamesonii (Gérbera). O experimento foi realizado entre o outono e o inverno de 2002, junto à área experimental do Departamento de Ciências Exatas, da E.S.A. "Luiz de Queiroz", Universidade de São Paulo, em Piracicaba, SP. Foi instalado um ambiente protegido, sub-dividido em três partes iguais. Um dos ambientes era coberto apenas pelo plástico leitoso (T1), enquanto os outros dois possuíam, ainda, malhas de sombreamento, que foram instaladas internamente, à altura do pé direito, sendo um com malha termo-refletora (Alumitela) (T2) e outro com malha preta (T3), ambas com 50% de sombreamento, fabricadas pela Solpack Ltda. Os sensores foram instalados no centro de cada ambiente protegido (sub-divisão) e em uma estação meteorológica automatizada, a 100 m do experimento, para coleta dos dados meteorológicos externos. Os ambientes protegidos afetaram os elementos meteorológicos diminuindo a radiação solar, a umidade relativa do ar durante o período diurno e a evapotranspiração das planta de Gérbera e aumentando a temperatura do ar. As transmitâncias médias da radiação solar pelas coberturas (plástico leitoso, plástico leitoso + malha termo-refletora e plástico leitoso + malha preta) foram, respectivamente 23, 11 e 7%. As temperaturas médias diárias do ar dentro dos ambientes protegidos foram cerca de 6 o C maiores no ambiente coberto pelo plástico leitoso e 3 o C maiores nos ambientes cobertos pelo plástico leitoso associado às malhas de sombreamento quando comparadas as temperaturas externas. Os tipos de cobertura, em função do microclima proporcionado, afetaram o desenvolvimento das plantas de Gérbera. O crescimento foi mais rápido sob o plástico leitoso e mais lento sob o plástico leitoso + malha preta. As plantas de Gérbera cultivadas sob os ambientes protegidos cobertos pelo plástico leitoso e pelo plástico leitoso + malha termo-refletora atenderam às exigências quanto ao número de botões florais. Isso não ocorreu no ambiente sob o plástico leitoso + malha preta. Quanto a altura da haste, as plantas cultivadas em ambiente protegido não apresentou valores médios superiores ao mínimo exigido, de 10 cm. Os microclimas proporcionados pelas coberturas constituídas por plástico leitoso e plástico leitoso + termo-refletora promoveram condições adequadas para o cultivo da Gérbera, durante o período entre o outono e o inverno. No entanto não pode-se afirmar que tais condições sejam representativas para todas as estações do ano, recomendando-se estudos futuros comparando-se diferentes materiais de cobertura em diferentes épocas do ano, visando um melhor entendimento do microclima na produção comercial de Gérbera. / The objective of this work was to evaluate the influence of white polyethylene as a greenhouse cover and its association with different shading screens (thermal screen and black screen) on the following environmental elements: incoming solar radiation (Qg), photosynthetically active radiation (PAR), temperature (T), relative humidity (RH) and evapotranspiration (ET) and also to evaluate the effects of the different microclimatic conditions on the growth, development and quality of Gerbera Jamesonii. The experiment was carried out between late Autumn and Winter of 2002 at the experimental area of the Exact Sciences Departament, Agricultural College "Luiz de Queiroz", at the University of São Paulo, in Piracicaba, State of São Paulo, Brazil. A greenhouse was installed, sub-divided into three parts. One of them was covered just with white polyethylene (T1), while the others had, yet, shading screens, that were installed within the greenhouse, being one covered with a thermal screen (Alumitela) (T2) and the other one with a black screen (T3), both with 50% of shading, manufactured by Solpack Ltda. The meteorological sensors were installed in the center of each sub-division of the greenhouse and an automatic weather station was located at 100m from the experimental area, to collect external meteorological data. The covers in the greenhouse affected the microclimate, decreasing Qg, PAR, RH and ET and increasing T. The average transmission of solar radiation by the covers (white polyethylene, white polyethylene + thermal screen and white polyethylene + black screen) were, respectively, 23, 11 and 7%. The mean daily air temperatures within the greenhouse were about 6 o C higher in the white polyethylene and 3 o C higher in the environments covered by white polyethylene associated with the shading screens in comparison to the external temperatures. The types of covers, forming different microclimates, affected the growth and development of Gerbera plants. The growth was faster under the white polyethylene and slower under the white polyethylene associated with black screen. The plants cultivated under the greenhouse covered with white polyethylene and with white polyethylene associated with thermal screen filled the requirements in relation to the number of flower buttons. However, the same was not observed in the environment covered with white polyethylene associated with black screen. About the stem size, all the cultivated plants under all environmental conditions not presented the minimum required value (10 cm). In general, the microclimate influenced by the different covers offered adequated conditions for the cultivation of Gerbera, during autumn and winter periods. However, it is not possible to be sure that these conditions are representative for the whole year stations, being recommended forward studies comparing different cover materials on different periods of the year, searching for a better comprehension of the microclimate influence on the commercial production of Gerbera.

The design processes for solar photovoltaic (PV) systems is improved to achieve higher reliability and reduced levelised cost of energy (LCOE) throughout this thesis. The design processes currently used in the development of PV systems are reviewed. This review process included embedding the author in a project to deliver four rooftop PV systems which totalled a megawatt of installed generating capacity, which at the time represented very significant system sizes. The processes used in this are analysed to identify improvement potential. Shortcomings are identified in three main areas: safety assurance, design process integration and financial optimisation. Better design process integration is required because data is not readily exchanged between the industry standard software tools. There is also a lack of clarity about how to optimise design decisions with respect to factors such as shading and cable size. Financial optimisation is identified as a challenge because current software tools facilitate optimising for maximum output or minimum cost, but do not readily optimise for minimum levelised cost of energy which is the primary objective in striving for grid parity. To achieve improved design process integration and financial optimisation, a new modelling framework with the working title SolaSIM is conceived to accurately model the performance of solar photovoltaic systems. This framework is developed for grid connected systems operating in the UK climate, but it could readily be adapted for other climates with appropriate weather data. This software development was conducted using an overarching systems engineering approach from design and architecture through to verification and validation. Within this SolaSIM framework, the impact of shading on array and inverter efficiency is identified as a significant area of uncertainty. A novel method for the calculation of shaded irradiance on each cell of an array with high computational efficiency is presented. The shading sub-model is validated against outdoor measurements with a modelling accuracy within one percent. Final verification of the over-arching SolaSIM framework found that it satisfied the requirements which were identified and actioned. The author installed the new CREST outdoor measurement system version 4 (COMS4). COMS4 is a calibrated system which measures 26 PV devices simultaneously. Validation of SolaSIM models against COMS4 found the modelling error to be within the 4% accuracy target except two sub-systems which had electronic faults. The model is validated against PV systems and found to be within the specified limits.

O objetivo deste trabalho foi avaliar a influência de ambientes cobertos com filme de polietileno branco leitoso e diferentes malhas de sombreamento (Termo-refletora –50% e Preta – 50%) nas seguintes variáveis ambientais: irradiância solar global, irradiância fotossinteticamente ativa, temperatura e umidade relativa do ar e evapotranspiração, e de seus respectivos microclimas no crescimento, no desenvolvimento e na qualidade da Gerbera jamesonii (Gérbera). O experimento foi realizado entre o outono e o inverno de 2002, junto à área experimental do Departamento de Ciências Exatas, da E.S.A. "Luiz de Queiroz", Universidade de São Paulo, em Piracicaba, SP. Foi instalado um ambiente protegido, sub-dividido em três partes iguais. Um dos ambientes era coberto apenas pelo plástico leitoso (T1), enquanto os outros dois possuíam, ainda, malhas de sombreamento, que foram instaladas internamente, à altura do pé direito, sendo um com malha termo-refletora (Alumitela) (T2) e outro com malha preta (T3), ambas com 50% de sombreamento, fabricadas pela Solpack Ltda. Os sensores foram instalados no centro de cada ambiente protegido (sub-divisão) e em uma estação meteorológica automatizada, a 100 m do experimento, para coleta dos dados meteorológicos externos. Os ambientes protegidos afetaram os elementos meteorológicos diminuindo a radiação solar, a umidade relativa do ar durante o período diurno e a evapotranspiração das planta de Gérbera e aumentando a temperatura do ar. As transmitâncias médias da radiação solar pelas coberturas (plástico leitoso, plástico leitoso + malha termo-refletora e plástico leitoso + malha preta) foram, respectivamente 23, 11 e 7%. As temperaturas médias diárias do ar dentro dos ambientes protegidos foram cerca de 6 o C maiores no ambiente coberto pelo plástico leitoso e 3 o C maiores nos ambientes cobertos pelo plástico leitoso associado às malhas de sombreamento quando comparadas as temperaturas externas. Os tipos de cobertura, em função do microclima proporcionado, afetaram o desenvolvimento das plantas de Gérbera. O crescimento foi mais rápido sob o plástico leitoso e mais lento sob o plástico leitoso + malha preta. As plantas de Gérbera cultivadas sob os ambientes protegidos cobertos pelo plástico leitoso e pelo plástico leitoso + malha termo-refletora atenderam às exigências quanto ao número de botões florais. Isso não ocorreu no ambiente sob o plástico leitoso + malha preta. Quanto a altura da haste, as plantas cultivadas em ambiente protegido não apresentou valores médios superiores ao mínimo exigido, de 10 cm. Os microclimas proporcionados pelas coberturas constituídas por plástico leitoso e plástico leitoso + termo-refletora promoveram condições adequadas para o cultivo da Gérbera, durante o período entre o outono e o inverno. No entanto não pode-se afirmar que tais condições sejam representativas para todas as estações do ano, recomendando-se estudos futuros comparando-se diferentes materiais de cobertura em diferentes épocas do ano, visando um melhor entendimento do microclima na produção comercial de Gérbera. / The objective of this work was to evaluate the influence of white polyethylene as a greenhouse cover and its association with different shading screens (thermal screen and black screen) on the following environmental elements: incoming solar radiation (Qg), photosynthetically active radiation (PAR), temperature (T), relative humidity (RH) and evapotranspiration (ET) and also to evaluate the effects of the different microclimatic conditions on the growth, development and quality of Gerbera Jamesonii. The experiment was carried out between late Autumn and Winter of 2002 at the experimental area of the Exact Sciences Departament, Agricultural College "Luiz de Queiroz", at the University of São Paulo, in Piracicaba, State of São Paulo, Brazil. A greenhouse was installed, sub-divided into three parts. One of them was covered just with white polyethylene (T1), while the others had, yet, shading screens, that were installed within the greenhouse, being one covered with a thermal screen (Alumitela) (T2) and the other one with a black screen (T3), both with 50% of shading, manufactured by Solpack Ltda. The meteorological sensors were installed in the center of each sub-division of the greenhouse and an automatic weather station was located at 100m from the experimental area, to collect external meteorological data. The covers in the greenhouse affected the microclimate, decreasing Qg, PAR, RH and ET and increasing T. The average transmission of solar radiation by the covers (white polyethylene, white polyethylene + thermal screen and white polyethylene + black screen) were, respectively, 23, 11 and 7%. The mean daily air temperatures within the greenhouse were about 6 o C higher in the white polyethylene and 3 o C higher in the environments covered by white polyethylene associated with the shading screens in comparison to the external temperatures. The types of covers, forming different microclimates, affected the growth and development of Gerbera plants. The growth was faster under the white polyethylene and slower under the white polyethylene associated with black screen. The plants cultivated under the greenhouse covered with white polyethylene and with white polyethylene associated with thermal screen filled the requirements in relation to the number of flower buttons. However, the same was not observed in the environment covered with white polyethylene associated with black screen. About the stem size, all the cultivated plants under all environmental conditions not presented the minimum required value (10 cm). In general, the microclimate influenced by the different covers offered adequated conditions for the cultivation of Gerbera, during autumn and winter periods. However, it is not possible to be sure that these conditions are representative for the whole year stations, being recommended forward studies comparing different cover materials on different periods of the year, searching for a better comprehension of the microclimate influence on the commercial production of Gerbera.

This paper discusses the relationship between the shape of the shading, the surface whose depth at each point equals the brightness in the image, and the shape of the original surface. I suggest the shading as an initial local approximation to shape, and discuss the scope of this approximation and what it may be good for. In particular, qualitative surface features, such as the sign of the Gaussian curvature, can be computed in some cases directly from the shading. Finally, a method to compute the direction of the illuminant (assuming a single point light source) from shading on occluding contours is shown.