Just call this after you finish moving your bones and it should work :

armature->processBonesLinking();
armature->updateBonesSkinMatrix();

So, to summary here is a code to rotate a bone :

if(mesh)
{
       MArmature * armature = mesh->getArmature();
       if(armature)
       {
           MOBone * bone = armature->getBone(0); // be sure the bone exist
           bone->addAxisAngleRotation(MVector3(1, 0, 0), 10);
            
           armature->processBonesLinking();
           armature->updateBonesSkinMatrix();
       }
}

apparently there are well bones in the .mesh file :

here is the all .mesh

thanks for helping me

Also, I looked at your behavior code again,
you do : "bone->addAxisAngleRotation(vector,i);"
but "i" is equal to zero, so it won't add any rotation,

try : "bone->addAxisAngleRotation(vector, 10);"

in blender :
I created a plane that I subdivided 5-6 times and a single bone that I extruded 3 times.
I selected the plane and the bone and "ctrl+p -> armature deform with empty group".
and for each bone  I selected some faces that I assigned to the bone.

and I exported this (mesh + armature) in maratis mesh without "armature anim".

In Maratis :
I imported the mesh and gave to it my behavior

do you see an error somewhere, please ?

"input->onKeyDown("MOUSE_BUTTON1")" is launched only 1 frame just after you press the mouse button (not every frames).
You maybe want to use "isKeyPressed("MOUSE_BUTTON1")".

You maybe also have animation keys that cancel your changes,
try to not export, or delete the Armature Animation file from Blender (.maa),
or use the piece of code I gave you in the previous post to remove keys for a specific bone.

maybe you can help by studying how to improve the Blender python script exporter
to export Blender shape keys ?

thank you for you fast response
I am afraid it's quite over my faculties, I am sorry.

I made a very basic behavior to test mesh deforming by moving a bone, but the mesh didn't deform itself, can you see where the problem is, please ?

to move a bone, you have access to all the MObject3d functions (MOBone derive from MObject3d),
for example, the rotation/translation (there is a lot more, you can look at MObject3d.h for more detail) :

bone->setEulerRotation(euler);
bone->addAxisAngleRotation(axis, angle);
bone->setPosition(position);

Be just careful that there is no keyframes associated with the bone, or it will discard your changes.
If you want to remove keyframes for a specific bone, lets say the bone 0 for example, you can do :

MArmatureAnim * armatureAnim = mesh->getArmatureAnim();
if(armatureAnim)
{
    // get bones anim array
    MObject3dAnim * bonesAnim = armatureAnim->getBonesAnim();

    // clear bone 0 keys
    bonesAnim[0].clearPositionKeys();
    bonesAnim[0].clearScaleKeys();
    bonesAnim[0].clearRotationKeys();
}

To play/stop animation (you can look at MOEntity.h for more animation related functions) :

entity->changeAnimation(animationId);

And for shape keys animation, I started working on it and wrote the MMorphingData class,
but I didn't finished to implement it, maybe you can help by studying how to improve the Blender python script exporter
to export Blender shape keys ?

Cheers,
Anaël.

suppose we have a MOBone named Bone0, how can we move him (Euler rotation like in Blender Pose mode, for example ) ?
how can we, with maratis Engine, play, stop and change mesh animations ?
and finally, does animations using shape keys work in maratis ?

What do you mean by "stock them" ?
Otherwise, to get bones from a mesh entity in c++, you can do like that :

MEngine * engine = MEngine::getInstance();
MLevel * level = engine->getLevel();

// get current scene
MScene * scene = level->getCurrentScene();

// get bone 0 from a mesh entity
MOEntity * entity = scene->getEntityByName("MyEntity");
if(entity)
{
    MMesh * mesh = entity->getMesh();
    if(mesh)
    {
        MArmature * armature = mesh->getArmature();
        if(armature)
        {
            MOBone * bone = armature->getBone(0); // get bone 0
        }
    }
}

I thought that they were considered like mesh children but they aren't.