[Bf-python] How to get inside faces from inside verts?

[joe]

I'd suggest asking for help on blenderartists or
irc://irc.freenode.net/blendercoders , I'm a little too tired to give
good answers at the moment.  :-/

Anyway, there should be a way of extracting the scale and rotation
part of a matrix (I believe the API has stuff for that) so I'd suggest
doing that, then creating a function that puts vertices through a
round-trip, first applying rot/scale based on the object matrix (don't
forget to zero the rot/scale fields after applying), then deapplying
it.  This will ensure that you have the order of transformations
correct.

Joe

On Thu, May 21, 2009 at 3:59 PM,  <lynx.abraxas at freenet.de> wrote:
> On 21/05/09 15:23:38, joe wrote:
>> What do you want?  The global positions of each vertex?  Or in
>> relation to the object center?
>
> I  would like the ellipsoid-obj to be translated where as their rot. and scale
> should be applied to the mesh. I think I got that with:
>
>   mat= B.Mathutils.Matrix([dl[6],dl[7],dl[8], 0],  [dl[9],dl[10],dl[11],  0],
> [dl[12],dl[13],dl[14], 0], [0,0,0,1])#octave: v' #why is this correct???
>   #mat=  B.Mathutils.Matrix([dl[6],dl[9],dl[12],  0],   [dl[7],dl[10],dl[13],
> 0], [dl[8],dl[11],dl[14], 0], [0,0,0,1])#octave: v
>
>   local_rot(ob, mat)
>   ob.setSize(dl[0], dl[1], dl[2])
>   ###ob.setLocation(dl[3], dl[4], dl[5])#transl obj and the mesh
>   me= ob.getData(mesh=1) #blender shows the obj. according to its matrix
>   me.transform(ob.matrix)#but does not apply it on the obj verts
>   ob.setMatrix(ob.matrix.identity())#set identity to avoid double effect
>   ob.setLocation(dl[3], dl[4], dl[5])#transl obj only not the mesh
>
>
> In the next step I want a  copy  of  an  ellipsoid  mesh  which  I  apply  the
> trnslation  of  the  ellipsoid  object on (just for pointInside). But the copy
> should not be linked to the ellipsoid object so that the mesh  of  the  object
> stays untouched by the translation of the (copied) mesh.
>
> All types of coping I tried some how kept a link to the original object:
>
>   ellmesh= ell.getData(mesh=1)
>   ellmesh= bpy.data.meshes.get(ell.getData(name_only=1,mesh=1))
>   ellmesh.get(ell.getData(name_only=1,mesh=1))
>   ellmesh= copy.copy(ell.getData(mesh=1))
>
> Is it possible?
> Do You know how?
>
> Thanks for Your help
> Lynx
>
>  To only apply the rot/scale, I believe
>> you can simply multiply (do this temporarily though, don't store the
>> result back in the mesh) with the rotation/scale matrix, which I
>> believe is something like:
>>
>> (matrix.rotationPart() * matrix.scalePart()) * vert_co
>>
>> . . .but I could be wrong, look it up in the docs.  It'd help if you
>> could give a more complete description of what your trying to do.
>>
>> Joe
>>
>> On Thu, May 21, 2009 at 11:17 AM,  <lynx.abraxas at freenet.de> wrote:
>> > On 20/05/09 17:33:20, joe wrote:
>> >> If applying rot/scale works, then it means your script isn't properly
>> >> taking the object matrix into account.  To calculate the final
>> >> transformed position of a vertex, you have to multiply it with the
>> >> object's matrix, like so:
>> >
>> > Is this OK too?
>> >
>> >   ellmesh= ell.getData(mesh=1)
>> >   ellmesh.transform(ell.matrix)  #apply any transform, just in case it wasn't done already
>> >   ell.setMatrix(ell.matrix.identity())
>> >
>> >
>> > This sadly has the unwanted side effect that the ellipsoids have their blender
>> > centres at the global origin.
>> > Without  the matrix application they have their blender centers at the centers
>> > of each ellipsoid.
>> > I created the ellipsoids by adding a UVsphere at the origin, rotating, scaling
>> > and displacing it:
>> >
>> >
>> >   me= B.Mesh.Primitives.UVsphere(segments, rings, diameter)
>> >
>> >   sc= B.Scene.GetCurrent()          # get current scene
>> >   #http://www.blender.org/documentation/246PythonDoc/Object-module.html
>> >   obn= "Ellipsoid_%0.4d" % dl[15]
>> >   ob= sc.objects.new(me, obn) # add a new mesh-type object to the scene
>> >
>> >   #http://www.blender.org/documentation/246PythonDoc/Object.Object-class.html
>> >   mat= B.Mathutils.Matrix([dl[6],dl[7],dl[8], 0],  [dl[9],dl[10],dl[11], 0], [dl[12],dl[13],dl[14], 0], [0,0,0,1])
>> >
>> >   local_rot(ob, mat)
>> >   ob.setSize(dl[0], dl[1], dl[2])
>> >   ob.setLocation(dl[3], dl[4], dl[5])
>> >   me= ob.getData(mesh=1) #blender shows the obj. according to its matrix
>> >   me.transform(ob.matrix)#but does not apply it on the obj verts
>> >   ob.setMatrix(ob.matrix.identity())#set identity to avoid double effect
>> >
>> >
>> > Why is blender showing the ellipsoids correctly where as their verts are still
>> > the unit sphere until I apply the matrix to the mesh?
>> > Can You point me to some docs explaining this behavior?
>> > Is there a way to apply only rot and scale to the mesh but not the translation
>> > at creation time?
>> > How  can  I  later  some  how translate the mesh (for pointInside to work) but
>> > leave the object as it is?
>> >
>> > Well, at least I'm slowly getting what I want;)
>> >
>> > Thanks for any help
>> > Lynx
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>> >
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