Can not adjust the transform of a spatial after it was added to a bone

MGDSStudio · April 25, 2025, 12:29pm

I imported my models from Blender in JME3 (character, sword and shield).

Right now, I want to attach the shield in the left hand and the sword in the right hand of the character.
Blender

I followed the instructions from TestOgreAnim.java but the transform of the objects relative to the character is wrong. What can be wrong?

Kingdom of the dead warlock 2025-04-25 15-18-26 (online-video-cutter.com)

Maybe were the bones created wrong in Blender? Or I should mirror the position of the spatial (sword and shield) relative to the character-node inside the JME? I cannot see the source model of the Ogre, used in JME3-examples to determine the best practices.

Code to load the character:

private void loadPlayer() {
        String path = WrapperPathsCreationUtil.getPath(false, false, "Models", "Player", "Player.j3o");
        var player = (Node) assetManager.loadModel(path);
        ((Node) rootNode.getChild(0)).attachChild(player);
        enableAnimation(player);
        loadWeaponAndShield(player);
    }

code to load and attach the sword:

private void loadWeaponAndShield(Node person) {
        String shieldName = "Shield";
        String path = WrapperPathsCreationUtil.getPath(false, false, "Models",shieldName , shieldName  + ".j3o");
        this.shield = assetManager.loadModel(path);    
        
        String swordName = "Sword";
        path = WrapperPathsCreationUtil.getPath(false, false, "Models",swordName , swordName  + ".j3o");
        this.sword = assetManager.loadModel(path);
        this.sword.rotate(FastMath.PI, 0, 0);    //I have played already with the angles but can not determine the dependency
        
        SkinningControl skinningControl = person.getControl(SkinningControl.class);
        Node n = skinningControl.getAttachmentsNode(SHIELD_BONE_NAME);
        n.attachChild(this.shield);
        Node n1 = skinningControl.getAttachmentsNode(SWORD_BONE_NAME);
        n1.attachChild(this.sword);
    }

tonihele · April 25, 2025, 3:48pm

Well, for starters at least you should switch to GLTF and not use the Ogre XML. That is deprecated pretty much. That might even already solve the problem.

MGDSStudio · April 25, 2025, 4:46pm

I use GLTF. I talked not about the file format but about the code from the example. I have also tried to add the simple red box from the JME-example. And it appears also in same place as the sword. This is the example code:

        Box b = new Box(.25f, 3f, .25f);
        Geometry item = new Geometry("Item", b);
        item.move(0, 1.5f, 0);
        item.setMaterial(assetManager.loadMaterial("Common/Materials/RedColor.j3m"));
        Node n = skinningControl.getAttachmentsNode("hand.right");
        n.attachChild(item);

And this is the red box.

The ogre from the examples holds the box right, but I can not see the source orge armature.

Maybe I should set some checkBox by Blender-export? Or should I make the anchor-bones for the weapon and shield using an another method?

MGDSStudio · April 25, 2025, 5:12pm

I’m watching this video and it seems the sword makes the rotation right, but the translation must be from the left to the right (on the picture), but the sword makes the translation from backward to forward.

pspeed · April 25, 2025, 5:14pm

Attachment nodes “just work” for me… so I wonder if there is something wrong with your armature somehow.

MGDSStudio · April 25, 2025, 5:27pm

Where can I see your armature, which “just works”? Maybe some screenshot?

pspeed · April 25, 2025, 5:56pm

Do you any non-uniform scaling in your bones or anything like that? All transforms applied, and so on. No weird scaling of the model itself?

MGDSStudio · April 25, 2025, 8:37pm

I have nothing strange in the code, but I have tried to edit the character model in the SceneComposer and highlighted the low level mesh in the SceneExplorer. And it shows me something strange:

All the code is bellow:

@Override
    public void simpleInitApp() {
        GlobalVariables.initEngine(this);
        loadScene();
        loadPlayer();
        setCameraParams();
    }

    private void setCameraParams() {
        flyCam.setMoveSpeed(flyCam.getMoveSpeed() * 25);
        var cameraPos = getCamera().getLocation();
        cameraPos.y += 15;
        cameraPos.z += 15;
        cameraPos.x += -10;
        getCamera().setLocation(cameraPos);
    }

    private void loadWeaponAndShield(Node person) {
        String shieldName = "Shield";
        String path = WrapperPathsCreationUtil.getPath(false, false, "Models",shieldName , shieldName  + ".j3o");
        this.shield = assetManager.loadModel(path);

        String swordName = "Sword";
        path = WrapperPathsCreationUtil.getPath(false, false, "Models",swordName , swordName  + ".j3o");
        this.sword = assetManager.loadModel(path);

        SkinningControl skinningControl = person.getControl(SkinningControl.class);
        Node n = skinningControl.getAttachmentsNode(SHIELD_BONE_NAME);
        n.attachChild(this.shield);
        Node n1 = skinningControl.getAttachmentsNode(SWORD_BONE_NAME);
        n1.attachChild(this.sword);
    }

    private void loadPlayer() {
        String path = WrapperPathsCreationUtil.getPath(false, false, "Models", "Player", "Player.j3o");
        var player = (Node) assetManager.loadModel(path);
        ((Node) rootNode.getChild(0)).attachChild(player);
        enableAnimation(player);
        loadWeaponAndShield(player);
    }

    private void enableAnimation(Node player) {
        var composer = player.getControl(AnimComposer.class);
        composer.setCurrentAction("ATTACK_1");
        composer.getCurrentAction().setSpeed(composer.getCurrentAction().getSpeed()*0.3f);
    }

    private void loadScene() {
        String path = WrapperPathsCreationUtil.getPath(false, false,  "Scenes", "Level_-1_test.j3o");
        var scene = (Node) assetManager.loadModel(path);
        rootNode.attachChild(scene);
    }

    @Override
    public void update() {
        super.update();
    }

pspeed · April 25, 2025, 9:56pm

When exporting the GLTF file from Blender, did you click the “y up” checkbox?

Edit: also make sure you “apply transforms” on your model. Hint: so far all of my model-related suggestions have been “things to fix in Blender”.

MGDSStudio · April 26, 2025, 5:57am

I also think it is the export problem, but I can not determine how to fix it. I have played with this check-box. It rotates the model but the blue mesh is also rotated relative to the visible model. The modifiers are applied. It could be intuitive right if I could rotate the low level mesh around 180 grad and the parent node around -90, but it is not successfully in the SceneComposer window.

MGDSStudio · April 26, 2025, 6:22am

I didn’t found any adequate method to set right export parameters and used the next export pipeline:

Export to .GLTF
Import in Blender again
Rotate the mesh
Export to .GLTF again
Import in JME3

And I receive the next model. I think, something should be changed in my original .BLEND model to avoid the unnecessary imports.

pspeed · April 26, 2025, 6:25am

These all seem like “forgot to apply transforms” problems to me.

capdevon · April 26, 2025, 11:26am

Quick tip for Blender before exporting to glTF: it’s a good practice to apply rotation & scale to your models first. This ensures all rotation values are reset to 0 on the X, Y, and Z axes, and all scale factors are 1 on the X, Y, and Z axes. You can do this by selecting your object, then in the “Object” menu, go to “Apply” and choose “Rotation & Scale”. This helps avoid unexpected transformations in your final glTF file!

From the image you posted it looks like you did not apply the Rotations before exporting the model

MGDSStudio · April 26, 2025, 1:41pm

I didn’t even watch the global rotation patameter. If I right understood I can not change this parameter inside the SceneComposer-window (it is gray on your screenshot) and I can change it only in Blender (or another 3D software). Is it right?

capdevon · April 26, 2025, 2:15pm

Yes, exactly, but just a note: the screenshot of the SDK is yours, not mine.

MGDSStudio · April 26, 2025, 5:09pm

Thanks, I have seen in Blender that my armature has two rotations. When I press “Ctrl+A” - I can apply this manipulations and after that - the armature of the model will appear in the same place as the mesh.