Objective

2

Fracturing has been widely applied in video games

films

and other industries. Fracturing simulation has attracted increasing attention in the field of computer graphics. Particularly

with the rapid development of virtual reality over the past few years

considerable demands have been placed on the diversity of fracturing results and real-time fracturing in a virtual scene. An improved fracturing result could significantly strengthen the realistic experience of players. In physics-based simulation method

the work of rigid body fracture simulation has been gradually conducted from the early inelastic deformation model to simulate the inelastic behavior to the mass-spring model and then to the fracture mechanism based on the tetrahedral model. To improve the realistic sense of fracturing effect as much as possible

numerous scholars have focused on enriching the detail expression of cracks during fracturing. During the continuous exploration of the simulation of physical phenomena in the real world

several physics engines have appeared in succession to simulate fragmentation and explosion in the real world. In recent years

significant progress has also been achieved in simulating the fragmentation of thin-plate type materials

such as paper

which renders the real-life fracturing phenomenon further varied on a computer. In the non-physical method of rigid body fracturing

the Voronoi diagram-based fracturing method plays a main role. However

the rigid body fracturing method has several disadvantages. First

the method based on physical force analysis does not work well in the situation where real-time is highly demanded

and the instant fracturing effect produced by the fracturing simulation based on non-physical method lacks diversity. Second

in most games

models often have been pre-fractured during their authoring time. When fracturing occurs

the original models are simply replaced by the pre-fractured one. This type of method significantly increases the authoring time of the designer and reduces the diversity. Most of the early works in film use the miniature model to simulate the crushing of large-scale scenes

such as the collapse of high-rise buildings. This type of method also lacks realism. To obtain real-time fracturing and diversified effects in fracturing simulation

a method applicable to diversified types is proposed

namely

a real-time rigid body fracturing method.

Method

2

During the fracturing simulation

the type of seed generation (three types of seed generation are available:completely random

evenly distributed with disturbance

and radiation) should be selected first. Then

sweep plane algorithm is used to generate the Voronoi diagram

based on which space partition is conducted on the model. During this process

to avoid the situation in which the seed points concentrated in a local area are too much or worse in the global area

sparse processing has been introduced:when multiple seed points are separated from each other by a certain threshold

the average value of the position of these seed points is selected as one seed point. Then

by means of a simulation pattern of fracture behavior (two types of simulation pattern:explosion and collapse)

the external force when rigid-body fracturing is simulated and collision detection

following the impact process of the broken fragments

is also simulated. Finally

rendering and display follows.

Result

2

Through a combination of different seed point-generating types and simulation patterns of fracture behavior

the diversified effect of fracturing are simulated. The real-time requirement can be satisfied. In a single rigid-body model fracturing simulation

the frame rate can reach 75 fram/s with 200 broken fragments. In further complex scenarios (e.g.

a building) where approximately 150 fracturing objectives with three types of materials are available

the frame rate can also reach 50 fram/s to cause the fracturing effect in this complex situation

not only to meet the diversity of fracturing effect but also to meet the real-time requirements

in the fracturing of different building components using different fracturing simulation types

through the combination of different types of seed point generation and fracture behavior simulation. A number of less affected parts from each other are broken at the same time. After comparison with some existing methods

the method used in this article achieves a better balance between computational efficiency (compared with the physics-based method) and diversity of fracturing effects (compared with the Voronoi-based method).

Conclusion

2

A real-time rigid-body fracturing method applicable to multi-fracturing effect is proposed in this paper. On the one hand

this method possesses a real-time feature

and on the other hand

it also contributes to enhancing the diversity of rigid body fracturing. By combining different seed point-generating types and simulation patterns of fracture behavior

diversified fracturing effects can be achieved. In our future work

this method will be further improved and optimized to be applied to highly complex fracturing simulation.