Re: [Visualpython-users] Collision detection with VPython

[Bruce S. <Bru...@nc...>]

Also, in case you didn't spot this, look at the Visual documentation on 
the box object and the accompanying diagram.

Bruce Sherwood

Jonathan Brandmeyer wrote:

>On Mon, 2006-03-27 at 23:20 +0000, Miles Jacobs wrote:
>  
>
>>I've tried to make VPython work with PyODE (http://pyode.sourceforge.net).  
>>The blocks seem to collide properly but they often settle on their edges.  I 
>>probably misunderstand the rotation matrix provided by PyODE or the "up" 
>>method of VPython.
>>    
>>
>
>Both up and axis define the orientation of a VPython body ("angle" is
>not used for anything).  See src/prim.cpp for the full story (there are
>some corner cases that the code follows to avoid degeneration).  The
>following is a reasonable approximation of what happens in there:
>
># Returns the direction cosine matrix of a VPython renderable body
># The result is a right-handed 3x3 orthonormal matrix
>def DCM( renderable):
>	z_axis = renderable.axis.cross( renderable.up).norm()
>	y_axis = z_axis.cross( renderable.axis).norm()
>	x_axis = renderable.axis.norm()
>	# Can probably use Tensor here...
>	ret = Numeric.array( shape=(3,3), type=Numeric.Float64)
>	ret[:,0] = x_axis
>	ret[:,1] = y_axis
>	ret[:,2] = z_axis
>	return ret
>
># Set the orientation of a renderable object from a 3x3 direction 
># cosine matrix, while retaining scaling information on the Visual
># object.
># renderable: A VPython renderable object
># DCM: A right-handed 3x3 orthonormal matrix
># returns: None
>def move_renderable_from_DCM( renderable, DCM):
>	renderable.axis = vector(DCM[:,0]) * renderable.axis.mag
>	renderable.up = vector(DCM[:,1])
>
>  
>
>>  Any help would be appreciated.  The VPython "cubes" get 
>>their positional and angular information from the PyODE "bodies".
>>    
>>
>
>HTH,
>-Jonathan
>
>
>
>
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