Author Topic: Blended Vertex Assignments  (Read 2752 times)

Offline cyberkilla

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Blended Vertex Assignments
« on: February 10, 2007, 03:38:25 pm »
In OgreXML format, there are Blended Vertexes.

I do not fully understand these.
Anyone got some documents on them?

I found this:
Quote

A blended vertex is how one bone shares a vertex with another bone.  Like a raw vertex, it has an offset in 3D space and a normal, but instead of a 2D texture point, it has a reference to a raw vertex (necessarily on a different bone?) and the blending info.  When applied, it modifies (deforms) the effective position and normal of the raw vertex.


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Offline EgonOlsen

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Blended Vertex Assignments
« Reply #1 on: February 10, 2007, 07:47:46 pm »
No idea... :?:

Offline cyberkilla

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Blended Vertex Assignments
« Reply #2 on: February 10, 2007, 07:52:39 pm »
Oh good, so its not just me:)

Something about vertexes being joined to multiple bones.
I dont like it. No way to turn it off.
Perhaps some form of intelligent ignorance on my importers part, will remove the problem:)
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Offline halcor

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Blended Vertex Assignments
« Reply #3 on: February 12, 2007, 09:36:58 am »
Yes,  I suppose it is about how multiple bones influence a vertex.
See what Blender vertex groups are:
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Advanced_Tutorials/Advanced_Animation/Guided_tour/Mesh/vg

Think about a blended vertex as a vertex that belongs to multiple vertex groups. By weight painting you tell how important each vertex group is for each vertex. So the final position of a vertex is determined by, say 10% of the movement of the bone A, 70% of the movement of bone B and 20% - bone C (bones A, B, C assigned to vertex groups vgA, vgB, vgC).
This method sure allows more flexible animations, but also is more complex both for animation and for implementation.

I suppose as Blender has advanced bone system and is open source you can look at the source and documentation for inspirations :)

Offline cyberkilla

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Blended Vertex Assignments
« Reply #4 on: February 12, 2007, 10:04:40 am »
Yes, I was reading something about this in the Ogre documentation:).

Thank you for your thoughts on the matter.
I was hoping it would be a mere ratio system, as you believe.
It will be interesting to see some screenshots, so ill get some online later today;).
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