Friction Rendering using God Object

1
Friction Rendering using God Object

• Haptics Project4
• 2006.6.19
• CSE 20065160 ???

2
Friction model

• F µ (PHIP Pgodobj)udir
• Static friction and dynamic friction
• It works as a simple spring on static friction.

GodObjcur
Ffriction
HIPcur
3
Magnitude

• Magnitude of friction is in direct propotion to
  PD.
• Static friction
• F µstatic(PHIP Pgodobj) (difference of
  godobj.)
• Dynamic friction
• F µdynamic(PHIP Pgodobj) (tolerance)

F
Static friction
Dynamic friction
difference of godobj.
tolerance
0
4
Direction

• We can use the position of HIP or the position of
  god object.
• HIP position has the normal component of surface.
• With the position of god object we can compensate
  the sudden change of force direction.
• Udir(t) Pgodobj(t-1) Pgodobj(t)

5
Special case

• When the first contact occurs, the wrong friction
  force can be calculated.

HIPprev
b
GodObjcur
a
HIPcur
6
Performance Tests

• At human model, it showed 23kHz
• At bottle model, it showed about 4kHz

7
Conclusion

• I implemented friction based on real physics
  using god object.
• Feel it now!