A Process to Create Dynamic Landscape Paintings Using Barycentric Shading with Control Paintings

In this work, we present a process that uses a Barycentric shading method to create dynamic landscape paintings that change based on the time of day. Our process allows for the creation of dynamic paintings for any time of the day using simply a limited number of control paintings. To create a proof of concept, we have used landscape paintings of Edgar Payne, one of the leading landscape painters of the American West. His specific style of painting that blends Impressionism with the style of other painters of the AmericanWest is particularly appropriate for the demonstration of the power of our Barycentric shading method

Developing Generalized Cross Hatching Shader Approach for Non-Photorealistic Rendering

In this research, I present a method for rendering a geometric scene that has the look and feel of artistic hand drawings, particularly using a medium such as charcoal or crosshatching. While there have been many approaches to non-photorealistic (NPR) renderings in the past two decades, there seems to be very little research done on how to obtain such charcoal or cross-hatching effects, especially with attention to reflections and specularity, which often at times seems to break the illusion of the drawing effect. I developed a new class of techniques, using a Barycentric shading method, that allows the non-photorealistic rendering of a variety of artistic drawing styles. My approach can be summarized as follows: (1) a Barycentric shader that can provide generalized crosshatching with opaque multi-textures, (2) a Barycentric shader using transparent multitextures, and (3) a texture synthesis method that can automatically produce crosshatching textures from any given image

A study of how Chinese ink painting features can be applied to 3D scenes and models in real-time rendering

Past research findings addressed mature techniques for non-photorealistic rendering. However, research findings indicate that there is little information dealing with efficient methods to simulate Chinese ink painting features in rendering 3D scenes. Considering that Chinese ink painting has achieved many worldwide awards, the potential to effectively and automatically develop 3D animations and games in this style indicates a need for the development of appropriate technology for the future market. The goal of this research is about rendering 3D meshes in a Chinese ink painting style which is both appealing and realistic. Specifically, how can the output image appear similar to a hand-drawn Chinese ink painting. And how efficient does the rendering pipeline have to be to result in a real-time scene. For this study the researcher designed two rendering pipelines for static objects and moving objects in the final scene. The entire rendering process includes interior shading, silhouette extracting, textures integrating, and background rendering. Methodology involved the use of silhouette detection, multiple rendering passes, Gaussian blur for anti-aliasing, smooth step functions, and noise textures for simulating ink textures. Based on the output of each rendering pipeline, rendering process of the scene with best looking of Chinese ink painting style is illustrated in detail. The speed of the rendering pipeline proposed by this research was tested. The framerate of the final scenes created with this pipeline was higher than 30fps, a level considered to be real-time. One can conclude that the main objective of the research study was met even though other methods for generating Chinese ink painting rendering are available and should be explored

Developing Generalized Cross Hatching Shader Approach for Non-Photorealistic Rendering

In this research, I present a method for rendering a geometric scene that has the look and feel of artistic hand drawings, particularly using a medium such as charcoal or crosshatching. While there have been many approaches to non-photorealistic (NPR) renderings in the past two decades, there seems to be very little research done on how to obtain such charcoal or cross-hatching effects, especially with attention to reflections and specularity, which often at times seems to break the illusion of the drawing effect. I developed a new class of techniques, using a Barycentric shading method, that allows the non-photorealistic rendering of a variety of artistic drawing styles. My approach can be summarized as follows: (1) a Barycentric shader that can provide generalized crosshatching with opaque multi-textures, (2) a Barycentric shader using transparent multitextures, and (3) a texture synthesis method that can automatically produce crosshatching textures from any given image

Shading with Painterly Filtered Layers: A Process to Obtain Painterly Portraits

In this thesis, I study how color data from different styles of paintings can be extracted from photography with the end result maintaining the artistic integrity of the art style and having the look and feel of skin. My inspiration for this work came from the impasto style portraitures of painters such as Rembrandt and Greg Cartmell. I analyzed and studied the important visual characteristics of both Rembrandt’s and Cartmell’s styles of painting.These include how the artist develops shadow and shading, creates the illusion of subsurface scattering, and applies color to the canvas, which will be used as references to help develop the final renders in computer graphics. I also examined how color information can be extracted from portrait photography in order to gather accurate dark, medium, and light skin shades. Based on this analysis, I have developed a process for creating portrait paintings from 3D facial models. My process consists of four stages: (1) Modeling a 3D portrait of the subject, (2) data collection by photographing the subjects, (3) Barycentric shader development using photographs, and (4) Compositing with filtered layers. My contributions has been in stages (3) and (4) as follows: Development of an impasto-style Barycentric shader by extracting color information from gathered photographic images. This shader can result in realistic looking skin rendering. Development of a compositing technique that involves filtering layers of images that correspond to different effects such as diffuse, specular and ambient. To demonstrate proof-of-concept, I have created a few animations of the impasto style portrait painting for a single subject. For these animations, I have also sculpted high polygon count 3D model of the torso and head of my subject. Using my shading and compositing techniques, I have created rigid body animations that demonstrate the power of my techniques to obtain impasto style portraiture during animation under different lighting conditions

Programmable Image-Based Light Capture for Previsualization

Previsualization is a class of techniques for creating approximate previews of a movie sequence in order to visualize a scene prior to shooting it on the set. Often these techniques are used to convey the artistic direction of the story in terms of cinematic elements, such as camera movement, angle, lighting, dialogue, and character motion. Essentially, a movie director uses previsualization (previs) to convey movie visuals as he sees them in his minds-eye . Traditional methods for previs include hand-drawn sketches, Storyboards, scaled models, and photographs, which are created by artists to convey how a scene or character might look or move. A recent trend has been to use 3D graphics applications such as video game engines to perform previs, which is called 3D previs. This type of previs is generally used prior to shooting a scene in order to choreograph camera or character movements. To visualize a scene while being recorded on-set, directors and cinematographers use a technique called On-set previs, which provides a real-time view with little to no processing. Other types of previs, such as Technical previs, emphasize accurately capturing scene properties but lack any interactive manipulation and are usually employed by visual effects crews and not for cinematographers or directors. This dissertation\u27s focus is on creating a new method for interactive visualization that will automatically capture the on-set lighting and provide interactive manipulation of cinematic elements to facilitate the movie maker\u27s artistic expression, validate cinematic choices, and provide guidance to production crews. Our method will overcome the drawbacks of the all previous previs methods by combining photorealistic rendering with accurately captured scene details, which is interactively displayed on a mobile capture and rendering platform. This dissertation describes a new hardware and software previs framework that enables interactive visualization of on-set post-production elements. A three-tiered framework, which is the main contribution of this dissertation is; 1) a novel programmable camera architecture that provides programmability to low-level features and a visual programming interface, 2) new algorithms that analyzes and decomposes the scene photometrically, and 3) a previs interface that leverages the previous to perform interactive rendering and manipulation of the photometric and computer generated elements. For this dissertation we implemented a programmable camera with a novel visual programming interface. We developed the photometric theory and implementation of our novel relighting technique called Symmetric lighting, which can be used to relight a scene with multiple illuminants with respect to color, intensity and location on our programmable camera. We analyzed the performance of Symmetric lighting on synthetic and real scenes to evaluate the benefits and limitations with respect to the reflectance composition of the scene and the number and color of lights within the scene. We found that, since our method is based on a Lambertian reflectance assumption, our method works well under this assumption but that scenes with high amounts of specular reflections can have higher errors in terms of relighting accuracy and additional steps are required to mitigate this limitation. Also, scenes which contain lights whose colors are a too similar can lead to degenerate cases in terms of relighting. Despite these limitations, an important contribution of our work is that Symmetric lighting can also be leveraged as a solution for performing multi-illuminant white balancing and light color estimation within a scene with multiple illuminants without limits on the color range or number of lights. We compared our method to other white balance methods and show that our method is superior when at least one of the light colors is known a priori

Inter-color NPR lines: A comparison of rendering techniques

Renders of 3D scenes can feature lines drawn automatically along sharp edges between colored areas on object textures, in order to imitate certain conventional styles of hand-drawn line art. However, such inter-color lines have been studied very little. Two algorithms for rendering these lines were compared in this study - a faster one utilizing lines baked into the textures themselves and a more complex one that dynamically generated the lines in image space on each frame - for the purpose of determining which of the two better imitated traditional, hand-drawn art styles and which was more visually appealing. Test subjects compared results of the two algorithms side by side in a real-time rendering program, which let them view a 3D scene both passively and interactively from a moving camera, and they noted the differences between each technique\u27s relative line thicknesses - the key visual disparity - in order to reach final judgments as to which better adhered to artistic conventions and which was more appealing. Statistical analysis of the sample proportions that preferred each algorithm failed to prove that any significant difference existed between the two algorithms in terms of either of the above metrics. Thus the algorithm using baked lines appeared to be more recommendable overall, as it was known to be computationally faster, whereas the dynamic algorithm was not shown to be preferred by viewers in terms of conventionality or aesthetics

A Process to Create Dynamic Landscape Paintings Using Barycentric Shading with Control Paintings

In this work, we present a process that uses a Barycentric shading method to create dynamic landscape paintings that change based on the time of day. Our process allows for the creation of dynamic paintings for any time of the day using simply a limited number of control paintings. To create a proof of concept, we have used landscape paintings of Edgar Payne, one of the leading landscape painters of the American West. His specific style of painting that blends Impressionism with the style of other painters of the AmericanWest is particularly appropriate for the demonstration of the power of our Barycentric shading method

Interactive Ray Tracing Infrastructure

In this thesis, I present an approach to develop interactive ray tracing infrastructures for artists. An advantage of ray-tracing is that it provides some essential global illumination (GI) effects such as reflection, refraction and shadows, which are essential for artistic applications. My approach relies on massively paralleled computing power of Graphics Processing Unit (GPU) that can help achieve interactive rendering by providing several orders of magnitude faster computation than conventional CPU-based (Central Processing Unit) rendering. GPU-based rendering makes real time manipulation possible which is also essential for artistic applications. Based on this approach, I have developed an interactive ray tracing infrastructure as a proof of concept. Using this ray tracing infrastructure, artists can interactively manipulate shading and lighting effects through provided Graphical User Interface (GUI) with input controls. Additionally, I have developed a data communication between my ray-tracing infrastructure and commercial modeling and animation software. This addition extended the level of interactivity beyond the infrastructure. This infrastructure can also be extended to develop 3D dynamic environments to obtain any specific art style while providing global illumination effects. It has already been used to create a 3D interactive environment that emulates a given art work with reflections and refractions