Display of Surfaces from Volume Data
IEEE Computer Graphics and Applications
Fundamentals of digital image processing
Fundamentals of digital image processing
Efficient ray tracing of volume data
ACM Transactions on Graphics (TOG)
Comprehensible rendering of 3-D shapes
SIGGRAPH '90 Proceedings of the 17th annual conference on Computer graphics and interactive techniques
A non-photorealistic lighting model for automatic technical illustration
Proceedings of the 25th annual conference on Computer graphics and interactive techniques
Interactive technical illustration
I3D '99 Proceedings of the 1999 symposium on Interactive 3D graphics
Volume illustration: non-photorealistic rendering of volume models
Proceedings of the conference on Visualization '00
Introduction to Computer Graphics
Introduction to Computer Graphics
Digital Character Design and Painting
Digital Character Design and Painting
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A basic step for many illustration techniques is the extraction of silhouettes and shape lines, in order to enhance the object shape visible to the observer. This paper presents a new and very fast method to obtain silhouettes and shape lines in non-photorealistic volume rendering processes, based on ray-tracing using an octree for optimization. This method consists of extracting contours based on image buffers acquired during the calculation of intersections in ray-tracing process with the model. These image buffers are then combined to produce silhouettes and shape lines from the model. A substantial improvement with regard to other silhouette extraction methods in volumes is that this method does not require the user to define thresholds; furthermore, it is not based on the z-buffer and thus does not depend on the precision of the latter. Neither the camera position nor the direction affect the performance of the algorithm. Finally, the algorithm detects silhouettes for objects which are inside other objects that are distinguished only by their hue.