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I am learning to manipulate a model in Assimp in Visual Studio Express 2019 . So I load a model and it has 0 animations. And I want to apply some transformation to its bone maybe hand and see its effect in the obj format I export. Now to see the effect in obj format I have to apply changes to its vertices, so I have to apply transformation in bone hierarchically. But I don't get the idea , how to implement all this. I have seen oglDev tutorial 38 but can't understand it. So any help will be appreciated.

Here are the thinks I need help in->

1. How to apply some transformation to a bone and to all its child (consider a simple human model).

2. How to get the final location of vertex affected by the particular bone as for bone we have just transformation matrices , so how do I convert them to X,Y,Z coordinate to tell vertex position .

I am not using OpenGL.

I want to use simple C++ code in Assimp for all this.

Please refer here for additional progress and difficulties details : Wrong Bone Rotation in Assimp

John christen
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1 Answers1

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.obj format does not have support for skeletal animation (or any form of animation). You cannot rotate the bones that do not exist. You need to use a model format that supports skeletal animation and use a model that contains that data. Example formats include .fbx, .gltf, .dae (COLLADA).

skmr
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  • I am using obj format just to print the vertices position . I know skeletal animation can't be seen but what i want is to apply some transformation to bone (maybe any arm rotated by 90 degree) and then apply transformation relative to new bone positions to vertices and then check the new vertex position in obj format. – John christen Jun 11 '20 at 17:31
  • I have learnt to display model , now I want to apply any transformation . For that I read on many places that they apply the rotation matrix to parent node of mesh . What is meant by parent node ? Do they mean node->mRootNode ? And doesnt applying rotation to this node transform whole model by 90 degrees or whatever rotation whereas I only want from shoulder to wrist rotation ? – John christen Jun 11 '20 at 17:35