Session: 02-06-01: eXtended Reality & Digital Design

Paper Number: 147250

147250 - Volumetric Evaluation of Thickness of 3d Object Using Maximum Inscribed Cubes 

Accurate specification of the thickness of a part is crucial for mechanical product design. This parameter significantly impacts both the mass and rigidity of the product. Therefore, an essential requirement is a generalized definition of thickness that can be applied to any three-dimensional (3D) object with a complex shape. In addition, it is necessary to develop a technology that can easily visualize the indicated thickness. According to international standards, the thickness of a part is commonly specified by dimensions. The dimensions generally define the distance between two parallel planes and are inappropriate for defining the thickness of a shape with curved surfaces.

With the growing use of 3D computer-aided design (CAD) systems, new thickness definitions based on solid modeling technology have become common. For example, the sphere method defines the thickness of a point on a 3D surface as the diameter of the maximum sphere inscribed at the point. The authors proposed a new method for defining thickness, known as volumetric thickness. Unlike the previous method, which considers thickness as an attribute value of points on an object's surface, this new method considers thickness as an attribute of points inside a solid object. Specifically, the thickness of a point inside an object is defined as the diameter of the maximum inscribed sphere containing the point. This method provides a more accurate and comprehensive understanding of thickness, making it a valuable contribution to the field. Volume rendering provides an easy understanding of the distribution of volumetric thickness within a part.

Both methods use inscribed spheres to define thickness. The sphere method always evaluates the corners of a part as thin because only small spheres can be placed at the corners of the part. This tendency to detect corners thin remained even in the case of volumetric thickness. This study proposes a novel method for evaluating thickness using maximum inscribed cubes instead of spheres. The thickness of a point inside a solid object is defined as the width of the maximum inscribed cube containing the point, following the concept of volumetric thickness. The use of an inscribed cube allows for a more accurate indication of thickness. This is because a cube with the same width as the thickness of the part also fits at its corners, providing a more precise measurement. This method confirms that all the corners of the part have the same thickness, which aligns with the intuition of the designer.

An experimental software was developed to convert the part shape into a voxel model and calculate the thickness of the center point of each voxel using the maximum inscribed cube containing the point. Furthermore, a volume-rendering technique was developed to properly display the voxel model using the obtained thickness values. The software was implemented to visualize the thickness distribution inside a polyhedral model of a mechanical part, and its effectiveness was verified by applying it to several parts.

Presenting Author: Masatomo Inui Ibaraki University

Presenting Author Biography: Masatomo Inui is a professor in the Department of Mechanical Systems Engineering at Ibaraki University, Japan. His current research interests include geometric modeling and its application to the automation of mechanical manufacturing. Inui received his doctorate in precision machinery engineering from the University of Tokyo. He is a member of IEEE and ASME. Contact him at masatomo.inui.az@vc.ibaraki.ac.jp.

Authors:

Masatomo Inui Ibaraki University
Nobuyuki Umezu Ibaraki University