MGame::draw();

seems to erase the first draw (so you see only the x-ray object).
So the correct way to go is

engine->getRenderer()->drawScene(scene,camera);

or

scene->draw(camera);

Other solution is to add an option in MMaterial to ignore depth-test so the object won't be affected by the z-buffer,
but your material should use an additive blending mode to avoid self intersection issues (additive blending can be render in any order).

//custom draw
void MyGame::draw(void)
{
    MGame::draw();

    MRenderingContext* rendering = engine->getRenderingContext();
    rendering->disableDepthTest();
    MRenderer * renderer = engine->getRenderer();

    MOEntity * entity = myEntity;
    MMesh * mesh = entity->getMesh();
    MSubMesh* smeshs = mesh->getSubMeshs();
    MVector3* vertices = smeshs[0].getVertices();
    MVector3* normals = smeshs[0].getNormals();
    MVector3 * tangents = ?
    MColor * colors = ?
    renderer->drawDisplay(smeshs[0],smesh[0].getDisplay(0),vertices,normals,tangents,colors); //not accessible

I could only do ->drawScene but that will be pointless unless I have another scene which bring us in the first solution again.
Hrm.. I need some renderer->drawEntity() method lol.

there is multiple ways to do it,

I think the simpler way would be to create a second scene where you put only the objects you want to draw in xray.
Use a clone of the main scene camera to syncronise the perspective and render this scene on top of the main scene as a camera-layer : http://wiki.maratis3d.org/index.php?tit … ameraLayer

Another way would be to do that by hand in MGame::draw,
after the scene draw, you disable the depth test with MRenderingContext and you render the x-ray objects after.

To sort objects you can use MCore's "sortFloatList(int indexList[], float floatList[], int start, int end)"

Thank you it may be that one, I'll try soon.

x-ray! How could it not came to my mind! That's the word. So e.g. in a futuristic game you see behind a wall a 3d object that you couldn't see because the wall is rendered after it. I'll add the term in the thread title.
It's even used in Blender for the armature.

or do you just want to do a special effect ?

in Maratis the rendering order is managed by MRenderer (here fixedRenderer or standardRenderer),
in the standardRenderer it happen globally like that :

- get the list of objects visible in the camera view
- render all non-transparent sub-meshs from near to far in depth-test only (early Z test) and build occlusion culling
- render occlusion-culled non-transparent sub-meshs in random order
- render transparent sub-meshs in far to near order

It's a bit different in the iOS renderer for example (no early z test because iphone and iPad 3d card uses tiled rendering).

To sort objects you can use MCore's "sortFloatList(int indexList[], float floatList[], int start, int end)"

But all depends on what you want to achieve.

I think there is a specific term for this, but it doesn't come to mind.
By the way I want to render a 3D object before everything else even if it's far from the camera, so I can e.g. show what's behind a wall.

The first phrase that came to mind was "Clipping Plane"
The 2nd word that came to mind was "Draw Distance."

I think the 2nd one is the term.

Edit: Seems like both of those terms are good ones to research. They seem to work sorta the same. You could use one or both techniques. The term "Clipping Path" came up while researching Clipping Plane.

EDIT: thread title edited