LightGuider is a novel guidance-based approach to interactive lighting design, which typically consists of interleaved 3D modeling operations and light transport simulations. Rather than having designers use a trial-and-error approach to match their illumination constraints and aesthetic goals, LightGuider supports the process by simulating potential next modeling steps that can deliver the most significant improvements. LightGuider takes predefined quality criteria and the current focus of the designer into account to visualize suggestions for lighting-design improvements via a specialized provenance tree. This provenance tree integrates snapshot visualizations of how well a design meets the given quality criteria weighted by the designer's preferences. This integration facilitates the analysis of quality improvements over the course of a modeling workflow as well as the comparison of alternative design solutions. We evaluate our approach with three lighting designers to illustrate its usefulness.
In the scientific domain, several approaches automate or simplify light-source placement and orientation---either with procedural methods as suggested by Schwarz and Wonka @cite_11 , or by painting'' the parts of a scene for illumination @cite_3 @cite_15 @cite_8 @cite_23 @cite_28 @cite_41 . While these methods deliver solutions to certain aspects, they ignore the iterative, interactive workflow of lighting designers, in which a large variety of considerations (that may not all be quantifiable) play an important role. Other approaches focus on interactivity, and try to decrease the feedback cycles between modeling and simulation. Both @cite_37 and Kr " @cite_21 rely on fast, GPU-based simulations. Despite being efficient, they do not offer guided modeling proposals or methods to explore and compare parallel modeling tracks.
@cite_37 @cite_8 @cite_28 @cite_41 @cite_21 @cite_3 @cite_23 @cite_15 @cite_11
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This paper focuses on efficient rendering based on pre-computed light transport, with realistic materials and shadows under all-frequency direct lighting such an environment maps. The basic difficulty is representation and computation in the 6D space of light direction, view direction, and surface position. While image-based and synthetic methods for real-time rendering have been proposed, they do not scale to high sampling rates with variation of both lighting and viewpoint. Current approaches are therefore limited to lower dimensionality (only lighting or viewpoint variation, not both) or lower sampling rates (low frequency lighting and materials). We propose a new mathematical and computational analysis of pre-computed light transport. We use factored forms, separately pre-computing and representing visibility and material properties. Rendering then requires computing triple product integrals at each vertex, involving the lighting, visibility and BRDF. Our main contribution is a general analysis of these triple product integrals, which are likely to have broad applicability in computer graphics and numerical analysis. We first determine the computational complexity in a number of bases like point samples, spherical harmonics and wavelets. We then give efficient linear and sublinear-time algorithms for Haar wavelets, incorporating non-linear wavelet approximation of lighting and BRDFs. Practically, we demonstrate rendering of images under new lighting and viewing conditions in a few seconds, significantly faster than previous techniques. Faithful manipulation of shape, material, and illumination in 2D Internet images would greatly benefit from a reliable factorization of appearance into material (i.e. diffuse and specular) and illumination (i.e. environment maps). On the one hand, current methods that produce very high fidelity results, typically require controlled settings, expensive devices, or significant manual effort. To the other hand, methods that are automatic and work on 'in the wild' Internet images, often extract only low-frequency lighting or diffuse materials. In this work, we propose to make use of a set of photographs in order to jointly estimate the non-diffuse materials and sharp lighting in an uncontrolled setting. Our key observation is that seeing multiple instances of the same material under different illumination (i.e. environment), and different materials under the same illumination provide valuable constraints that can be exploited to yield a high-quality solution (i.e. specular materials and environment illumination) for all the observed materials and environments. Similar constraints also arise when observing multiple materials in a single environment, or a single material across multiple environments. Technically, we enable this by a novel scalable formulation using parametric mixture models that allows for simultaneous estimation of all materials and illumination directly from a set of (uncontrolled) Internet images. The core of this approach is an optimization procedure that uses two neural networks that are trained on synthetic images to predict good gradients in parametric space given observation of reflected light. We evaluate our method on a range of synthetic and real examples to generate high-quality estimates, qualitatively compare our results against state-of-the-art alternatives via a user study, and demonstrate photo-consistent image manipulation that is otherwise very challenging to achieve. An interactive and intuitive way of designing lighting around a model is desirable in many applications. In this paper, we present a tool for interactive inverse lighting in which a model is rendered based on sketched lighting effects. To specify target lighting, the user freely sketches bright and dark regions on the model as if coloring it with crayons. Using these hints and the geometry of the model, the system efficiently derives light positions, directions, intensities and spot angles, assuming a local point-light based illumination model. As the system also minimizes changes from the previous specifications, lighting can be designed incrementally. We formulate the inverse lighting problem as that of an optimization and solve it using a judicious mix of greedy and minimization methods. We also map expensive calculations of the optimization to graphics hardware to make the process fast and interactive. Our tool can be used to augment larger systems that use point-light based illumination models but lack intuitive interfaces for lighting design, and also in conjunction with applications like ray tracing where interactive lighting design is difficult to achieve. We present a system for the lighting design of procedurally modeled buildings. The design is procedurally specified as part of the ordinary modeling workflow by defining goals for the illumination that should be attained and locations where luminaires may be installed to realize these goals. Additionally, constraints can be modeled that make the arrangement of the installed luminaires respect certain aesthetic and structural considerations. From this specification, the system automatically generates a lighting solution for any concrete model instance. The underlying, intricate joint optimization and constraint satisfaction problem is approached with a stochastic scheme that operates directly in the complex subspace where all constraints are observed. To navigate this subspace efficaciously, the actual lighting situation is taken into account. We demonstrate our system on multiple examples spanning a variety of architectural structures and lighting designs.