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------------------------------------------------------------
revno: 3608
committer: Jan Stransky <jan.stransky@xxxxxxxxxxx>
timestamp: Wed 2015-03-04 13:51:37 +0100
message:
  box inertia computation correction
modified:
  py/utils.py


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=== modified file 'py/utils.py'
--- py/utils.py	2014-12-01 18:29:59 +0000
+++ py/utils.py	2015-03-04 12:51:37 +0000
@@ -220,7 +220,8 @@
 	b=Body()
 	b.shape=Box(extents=extents,color=color if color else randomColor(),wire=wire,highlight=highlight)
 	V=8*extents[0]*extents[1]*extents[2]
-	geomInert=Vector3(4*(extents[1]**2+extents[2]**2),4*(extents[0]**2+extents[2]**2),4*(extents[0]**2+extents[1]**2))
+	# I = m*dim**2/12. = (m=V) = V*(2*extent)**2/12. = V*extent**2*4/12. = V*extent**2/3.
+	geomInert=(V/3.)*Vector3(extents[1]**2+extents[2]**2,extents[0]**2+extents[2]**2,extents[0]**2+extents[1]**2)
 	_commonBodySetup(b,V,geomInert,material,pos=center,dynamic=dynamic,fixed=fixed)
 	b.state.ori=orientation
 	b.mask=mask