[Bf-python] 3DVec * 4x4Matrix issue

[Campbell Barton]

Oops, maybe it is. if so
vec*mat is alredy using overloading and has dome for a while now. my 
point is spesificly about a vec3d * mat4x4

Campbell Barton wrote:
> Correct me if Im wrong, but this isnt overloading..
> Its just how a vector and a matrix multiply together
>
> vec3d * mat3x3 is obvious
> vec3d * mat4x4 - in unclear whats best. apply transformation or not?
>
> From my experience its best to apply the translation, the are so many 
> more cases when you want it applied, then not.
>
>
> McCracken, Andrew wrote:
>> Hi,
>>
>> overloading * sounds a bit drastic to me.
>>
>> I would go for an object.vec3dtoworldspace3d(vec)
>>
>> or just object.toWorldspace3d(vec)
>>
>> I know very little about the BPY api tho.
>>
>> Cheers
>>
>>
>> -----Original Message-----
>> From: bf-python-bounces at projects.blender.org on behalf of Campbell 
>> Barton
>> Sent: Sat 7/22/2006 3:18 PM
>> To: Blender Foundation Python list
>> Subject: [Bf-python] 3DVec * 4x4Matrix issue
>>  
>> Hi, This was mentioned a while ago, but I dont think any conclusion 
>> was reached..
>>
>> A problem I come across almost weekly from new scripters is how to 
>> get the worldspace location of a vector from object data, a vert say 
>> (through emails end blenderartist python forum)
>>
>> world_vec= vec*matrix works if the vector  4D but for 3D vectors it 
>> dosent apply the translation.
>>
>> Solutions are ...
>>
>> mtx= ob.matrixWorld
>> vec_copy= Mathutils.Vector(vec)
>> vec_copy.resize4D()
>> vec=vec_copy*mtx
>> vec.resize3D()
>> or...
>>
>> mtx= ob.matrixWorld
>> vec=vec*mtx
>> vec= vec+mtx.translationPart()
>> or..
>>
>> do the matrix multiplication manually..
>>
>> Could we just have the matrix multiplication apply transformation to 
>> a 3D vector?
>>
>> - Cam
>>
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>>
>>
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>


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Campbell J Barton

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