Download - Soft body simulation
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Soft Body Simulation
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What is Soft body? A soft body is basically an object which changes its overall shape due to external forces acting on it. Some examples that we commonly see include cloth, balloons and jelly.
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Applications for soft body simulations:-
Computer Graphics (animation)
Virtual Reality
Games
And many more…
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Existing Soft Body Models Spring-Mass based models
- easy implementation, weak results
FEM, FEV based techniques
- great results, complicated implementation, slow
Fluid based model
- good results, not for realtime
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Purpose "...to create model which will be fast, easy in implementation and gives good soft bodies behavior."
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Problem statement To design a plugin for Unity developers that helps in simulation of interactive soft body (Jell-O like) with spring mass and pressure model in Unity
To develop an AR based Android application to visualize this simulation.
This soft body can be any given mesh and/or parts of a given mesh.
We can merge different meshes also.
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Spring Mass Pressure Model Spring :
Each edge of the mesh is converted into springs with a spring constant and a damping constant.
User can change these constants according to their needs.
Mass : Each vertex has a definite mass which can be
modified by the user. User can change Gravitational
force constant.
Pressure: Pressure is applied inside the mesh so that it
Can behave like a balloon. User can change Pressure constant.
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Background of Pressure Model Create Spring Mass System
Create a simple cloth.
Apply wind force (left -> right)
We will see a deformation in the cloth.
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Algorithm proposed Create closed shape of the cloth
And.. put "source of the wind" inside.
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Wind Source?? Wind source basically provide a pressure to the mesh.
We can consider a gas which will provide the necessary pressure.
- We will put an ideal gas inside of the body
- And apply some basic physics to it.
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Ideal Gas Approximation Pressure value is described by Ideal Gas Equation:
P V = nRT
P- pressure value
V- volume of the body
n- particles number
R- gas constant
T- gas temperature
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Pressure Force calculation We can calculate pressure to a point with this equation:-
And for pressure:-
Assume n, R and T are constant. So we have to calculate the volume of the body.
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Volume We use gauss theorem to calculate volume of the body.
Collision detection and response are also handled.
If F is a continuously differentiable vector field defined on a neighborhood of V, then we have
The left side is a volume integral over the volume V, the right side is the surface integral over the boundary of the volume V.
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Implementation
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NoveltyThe diagram below compares the existing spring mass model with the new spring mass with pressure model.
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AR based Android App - Uses Vuforia AR library.
- Designed to visualize soft body simulations of 3D figures from every angle and at every step of simulation.
- Start/Stop functionality.
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Results
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AR application
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Conclusion Pressure Model of Soft Body behavior
it is fast.
gives good Soft behavior in real time.
it is easy for implementation.
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Future Work Increase the performance of our algorithm to give better results in less amount of time.
Increase user interaction in the mobile app.
Design a mobile AR based game for better understanding of soft body for educational purposes.
Stabilize the system for inter-mesh collisions.
Collision with other rigid bodies and soft bodies would be incorporated.
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Thank You..!!