33 results about "Mass spring model" patented technology

Disclosed is an animation method of deformable objects using an oriented material point and generalized spring model. The animation method comprises the following steps of: modeling a structure of a deformable object into oriented material points and generalized springs; initializing forces and torques acting on the material points, calculating the forces acting on the material points owing to collision of the material points and gravity, calculating the spring forces and torques acting on the material points, obtaining new positions and postures of the material points; updating positions, velocities, postures and angular velocities of the material points based upon physics, and displaying and storing updated results. The oriented material point and generalized spring model of the invention contains the principle of the conventional mass-spring model, but can animate deformable objects or express their structures in more intuitive manner over the conventional mass-spring model. Also, the material point and generalized spring model of the invention can express elongate deformable objects such as hair and wrinkled cloth, which cannot be expressed in the prior art, so as to animate features of various objects.

The invention provides a three-dimensional garment and human model collision detection method and device. The method comprises the steps that a three-dimensional garment pattern piece corresponding to a to-be-displayed garment and a three-dimensional human model are obtained; collision parameters of all discrete grid points in the three-dimensional garment pattern piece are obtained, and a mass spring model corresponding to the three-dimensional garment pattern piece is built; when the mass spring model is moved to the collision position matched with the three-dimensional human model, collision detection is conducted on the mass spring model and the three-dimensional human model according to an algorithm of the bounding box tree to determine whether the three-dimensional garment pattern piece is actually attached to the three-dimensional human model or not. In this way, the display effect of the to-be-displayed garment on the three-dimensional human model is more vivid and truer; meanwhile, by means of the algorithm of the bounding box tree, collision detection between the three-dimensional garment pattern piece and the three-dimensional human model can be completed rapidly, and the real-time property of the whole process is guaranteed.

The invention discloses a soft tissue deformation simulation method based on a roll nonlinear anisotropic mass spring model, which comprises the following steps: 1) constructing a mass spring model, and determining initial elastic parameters of that mass spring model by a finite element method; 2) setting spring parameters in the deformation process according to the stress and strain relationshipof the muscle tissue; 3) parameterize describing that anisotropic characteristic of the soft tissue by constructing a mechanical equation of the spring; 4) constructing that dynamic equation of the mass spring model and solving it. The invention has the beneficial effect that the setting of the spring parameter in the mass spring model is solved, the anisotropy is parameterized, and an improved Euler algorithm is adopted in solving the dynamic equation of the mass spring model.

The invention relates to the technical field of node positioning in wireless sensor networks, in particular to a three-dimensional weighted centroid positioning method based on a mass-spring model. The positioning method includes the steps: in an initial phase, amending a weight of the three-dimensional weighted centroid positioning method, and estimating the initial positions of unknown nodes by the weighted centroid positioning method with the amended weight; in an optimizing phase, amending the measuring distance by the aid of error factors, adjusting the unknown nodes to the best positions by the method of the mass-spring model. The positioning method is applicable to positioning geometric peripheral nodes comprising anchor nodes and has the advantages of high positioning accuracy and strong robustness.

The invention provides a non-stretch cloth simulation oriented mass-spring model constraint method. By adopting the method, deformation repair of a structural spring in a mass-spring model can be realized by correcting the mass point position of the mass-spring model. The mass-spring model constraint method specifically comprises the following steps: in order to accelerate the convergence speed of constraint implementation, giving an optimal relaxation factor based on a topological structure and deformation of the structural spring and the like in the mass-spring model; according to deformation of a single structural spring, calculating components of position correction quantity of mass points at two endpoints along the spring direction; superposing the components of the position correction quantity of the same mass point; multiplying the superposition sum by the optimal relaxation factor, and taking the result as the position correction quantity of the mass point; and finally updating the mass point position so as to realize deformation repair of the structural spring. The mass-spring model constraint method has the beneficial effects that conservation between linear momentum andangular momentum of cloth can be ensured and the non-stretch cloth can be efficiently and stably simulated during the constraint implementation process, thus the method can be widely applied to non-stretch cloth simulation in virtual reality systems for film and video production, digital entertainment and other purposes.

The invention provides a flexible cable pose simulation method and device based on a bending composite mass-spring model. The method comprises establishing a physical property model of a flexible cable, and describing the anti-torsion characteristic of the flexible cable using distortion springs added to each segment of the flexible cable; obtaining the initial position of each discrete particle according to the overall length of the flexible cable and the number of the segments; determining discrete particles at two ends of the flexible cable as fixed points, and obtaining positional information of the fixed points; calculating stress information of other discrete particles of undetermined positional information of the flexible cable according to the physical property model; sequentially calculating balance positions of other discrete particles using the stress information and the initial positions, to obtain positional information of other discrete particles; and simulating a stable pose of the flexible cable according to the positional information of the fixed points of the flexible cable and the positional information of other discrete particles. The effect of simulation of the flexible cable can be more actual by adopting the flexible cable pose simulation method and device based on the bending composite mass-spring model, the reliability of the flexible cable during assembling can be ensured to some degree.

The invention relates to a system for dynamically simulating cloth tearing. The system establishes a cloth model by utilizing a mass spring model, so that cloth is decomposed into multiple triangular patches; then, cloth tearing is completed; a Half-edge data structure is added while modelling is carried out; related information of the position of a cloth vertex, the relationship between an edge and a vertex, the relationship among the length of the edge, a surface and the vertex and the adjacency relationship of the surfaces is stored; a bounding box distance field based on the Euclidean distance is created, and used for completing collision detection; the cloth tearing simulation efficiency is increased; a steel body model is created; the gravitational acceleration is added to a rigid body or the cloth, so that the rigid body and the clock are collided; and then, tearing is generated. The system disclosed by the invention can be widely applicable to dynamic analogue simulation of the cloth in design and manufacture and film and television entertainment.

The invention relates to the technical field of advanced manufacturing, in particular to an interactive deformation and measurement simulation method for manually measuring a girth of a nonrigid limb. The method comprises the following steps of: obtaining three-dimensional point cloud data of a limb surface through a laser scanner; obtaining a mesh surface model of the limb by using a triangular mesh reconstruction algorithm; defining a partial deformation area related to measurement and comprising a flexible rule coverage area, an external force spreading area and a compensation area and a control parameter; triangularizing the partial deformation area again to improve the mesh quality; dynamically calculating the change of a model volume when the limb deforms by utilizing the interactive deformation between a deformation simulation algorithm simulative flexible rule and the limb based on a mass-spring model; compensating the change of the volume by utilizing a volume compensation function; and calculating the girth by utilizing an RBF (Radial Basis Function) surface reconstruction algorithm based on the partial cloud point after the limb model deforms. The invention has visual effect and high measurement precision and satisfies the industrial requirement on time.

A tissue deformation method based on a mass spring and hydromechanics comprises the steps that firstly, a uniform triangular patch grid is established for a to-be-researched tissue according to medical data; secondly, a mass spring physical model is established on the established tissue grid model; thirdly, a fixed rigid body core and a generalized spring are established; fourthly, the established mass spring grid model is filled with a SPH model fluid; and fifthly, a rigid body which occupies certain space is set and used to transmit loads together with the fluid. The mass spring model is used to simulate skin deformation on the tissue surface; and the SPH model fluid and the rigid body are used to simulate a running mechanism of body fluids in the tissue. The invention provides the tissue deformation method based on the mass spring and the hydromechanics, wherein the method has high timeliness and can increase authenticity of simulation.

The invention discloses a gradient damping composite material based on a mass spring model and a preparing method of the gradient damping composite material, relates to damping composite materials and aims at solving the problems that an existing single-layer damping material is narrow in damping temperature range, and damping loss factors are low. The gradient damping composite material is composed of multiple damping layers, and each damping layer is composed of mass block particles wrapped by polyurethane elastomer and basalt flake fibers. The crosslinking degree of the polyurethane elastomer on the upper damping layer is larger than the crosslinking degree of the polyurethane elastomer on the lower damping layer. The preparing method comprises the steps that the mass block particles are added into polyurethane prepolymer to be subjected to the reaction, then, the polyurethane-wrapped elastomer is formed, the basalt flake fibers are then added, shearing and grinding are uniform, a chain extender and/or a curing agent are/is added according to the amount of the chain extender and/or the curing agent from low to high, and pouring liquid of all layers is obtained; layer-by-layer pouring is conducted according to the crosslinking degree from low to high, the composite material is obtained through curing, and the loss factor of the composite material at the temperature ranging from -40 DEG C to 1 DEG C ranges from 0.7 to 1.17. The gradient damping composite material can be used in the damping field.

In response to movement of an underlying structure, motion of complex objects connected to that structure may be simulated relatively quickly and without requiring extensive processing capabilities. A skeleton extraction method is used to simplify the complex object. Tracking is used to track the motion of the underlying structure, such as the user's head in a case where motion of hair is being simulated. Thus, the simulated motion is driven in response to the extent and direction of head or facial movement. A mass-spring model may be used to accelerate the simulation in some embodiments.

The invention discloses a soft tissue modeling method based on position constraint and a nonlinear spring. The method comprises the following steps: (1) constructing a soft tissue model formed by tetrahedron units formed by the nonlinear spring and a virtual body spring; (2) simulating the deformation behavior of the soft tissue model; (3) estimating the approximate position of each node, judging whether the state of a node constraint equation is changed or not, wherein constraints comprise spring length and curvature constraints; if the initial state of the equation is changed, correcting the node to a correct position within a reasonable range; if the initial state of the equation is not changed, indicating that the nonlinear spring and the virtual body spring simulate the deformation effect of the soft tissue; and (4) ending the single-step iteration of deformation calculation, and entering the next cycle. The non-linear spring system and the virtual body spring are adopted to simulate the biomechanical characteristics of the soft tissue, a new constraint equation is adopted to limit node displacement so as to enhance the stability of the model, and the defects that a traditional mass spring model is poor in accuracy and unstable are overcome.

The invention discloses an image processing method and a device for a 3D animation material, equipment and a medium. In one specific embodiment, the method comprises steps: based on a mass spring model, a 3D animation material used to surround a colliding body is converted to a mesh set, wherein the colliding body is converted to a corresponding cylinder structure and each mesh is a quadrilateral formed by four vertices; as for each mesh, the four vertices of the mesh are projected to a plane vertical to the medial axis of the colliding body to obtain four projection vertices of the mesh and a projection quadrilateral formed by the four projection vertices; the colliding body is projected in the plane to obtain a circle; whether the projection quadrilateral of each mesh is at least partially overlapped with the circle is determined; and if the projection quadrilateral of at least one mesh is at least partially overlapped with the circle, vertices of the at least one mesh are moved, and the projection quadrilateral obtained when the mesh after movement is projected again in the plane is not overlapped with the circle. Thus, the image when the 3D animation material passes through the colliding body can be detected and corrected.

The present invention proposes an improved wireless sensor network centroid positioning algorithm. The algorithm first uses the traditional centroid algorithm for rough positioning; then in order to reduce the requirements for the number of anchor nodes or the communication radius, unknown nodes with neighbor anchor nodes only use neighbors Anchor nodes are used for positioning, and unknown nodes without neighbor anchor nodes are positioned using unknown neighbor nodes that have been located; finally, the estimated distance from the node to the neighbor node is calculated based on the estimated position of the node, and then the average value of the estimated distance from the node to all neighbor nodes is used as The equilibrium length of the spring in the mass spring model, so as to make the distance from the node to all neighbor nodes equal as far as possible through the mass spring model, and reduce the positioning error.

The invention relates to the technical field of node positioning in wireless sensor networks, in particular to an anchor-free positioning method based on hop quantification and a mass-spring model. According to the positioning method, a coordinate system with a smaller error is built by the aid of a hop quantification method. Measured distance information is sufficiently used for quantizing the communication radius lengths of sensing nodes into a plurality of hops. The invention further provides an AMSO (adaptive mass-spring optimization) method based on the mass-spring model. The positions of a center node and all neighbor nodes are adjusted by the aid of the AMSO method, the positions of the sensing nodes are optimized by AMSO, and sensing node coordinates are prevented from local optimum in iterative optimization. The positioning method has the advantages of high positioning accuracy, robustness and convergence speed.

The invention relates to a wide-temperature-range damping vibration attenuation composite material and a preparation method thereof, and belongs to the technical field of functional materials. According to the method provided by the invention, zinc oxide crystal whiskers are subjected to surface treatment, the surface of the structure is better covered by a polymer chain segment, more interfacialdamping effects are generated when the chain segment moves, the chain segment is combined with cage-type polysilsesquioxane, slippage between the chain segment and the cage-type polysilsesquioxane caneffectively increase loss, a mass spring model is introduced, a polyurethane elastomer is regarded as a spring, the zinc oxide crystal whiskers with mass are used as a vibrator, local resonance is formed, finally the local resonance is dispersed in rubber, and syntony occurs between external vibration and an internal mass block while viscoelastic damping occurs, so that vibration is gradually attenuated; and from the overall structure of the damping composite material, the local resonance with the internal mass block and external viscoelastic damping have a synergistic effect, so that the damping performance of the damping composite material is improved.

The invention discloses a simulation and discretization method of offshore oil containment boom motion based on a signed distance function, comprising the following steps: simulation of oil containment boom motion based on a mass spring model is performed; discreteness of oil containment boom based on signed distance function. The invention adopts SDF-based method to carry out oil spill interactive simulation, which is more intuitive. When performing interactive processing, only the SDF value at the current location needs to be queried to determine whether the current location requires interactive processing. Compared with the traditional method is more convenient and more intuitive. The invention adopts the marine oil spill interaction method based on the SDF method, which has the naturalparallelism and can be transplanted into the GPU for parallel acceleration. In the process of oil containment boom SDF calculation, the calculation of each grid node can be assigned to a GPU core asneeded, which is very convenient for parallel acceleration. The invention can simulate the movement effect of the oil containment boom towing, and has higher physical reality.

A real-time simulation method for tissue deformation in laparoscopic surgery relates to the field of computer-aided medical treatment, and simulates soft tissue to guarantee viscoelasticity, incompressibility and other characteristics by using a mass spring model of a regular tetrahedron and a conical spring. The mass point spring model using the central regular tetrahedron unit and the conical spring is adopted, when deformation simulation is carried out on the soft tissue, the characteristics of incompressibility, viscoelasticity and the like of the soft tissue can be guaranteed, meanwhile, the simulation rate of about 30 FPS can be achieved, the requirement for real-time performance can be preliminarily met, and the method is suitable for simulation in an operation.

The invention relates to a method and a system for dynamic virtual simulation of a plant. The method comprises the following steps of according to a topology structure of the plant, establishing a mass spring model of the plant, and determining the number and quality of masses; according to the movement capturing feature point of the plant, capturing the movement of the plant within the continuous movement capturing time sequence, and recording the captured movement data frame; analyzing the movement data frame, obtaining the parameters of the mass spring model, and performing dynamic virtual simulation of the plant. The method has the advantages that by establishing a quantitative relationship between physical model parameters and real physical movement of the plant, the reasonableness and accuracy of the physical model parameters are effectively guaranteed, and the effect of virtual simulation of the plant is improved.

The method provides a hybrid suture line model based on a mass spring and a knotting method of the hybrid suture line model. According to the model, a torsion spring is added and a method of segmentalcalculation of the tension of a suture line is adopted based on a mass spring model, primitive collision detection is combined with a collision cluster method, and a limit on the maximum moving distance of vertexes of the suture line in a unit time step is added. By adopting the hybrid suture line model and the knotting method thereof provided by the invention, the internal tension of the sutureline can be realistically simulated, the collision phenomenon of false detection and missed detection can be effectively avoided, and the calculation accuracy of collision feedback force can be improved. Experiments show that compared with a traditional FTL suture line modeling method, the model and the knotting method provided by the invention are more realistic in visual rendering and more stable in dealing with complex knot simulations such as 'bowline'.