Irrlicht Engine

Hello. I've written a custom scene node with 4 vertices and 4 triangles (2 for face and 2 for backside). sadly, when i render the scene nodes which should be behind the others are in advance of them. What may be wrong?

Without seeing your code its hard to tell what might be wrong... however you might consider this...

make sure that you have the triangles vertices arranged in a counter clockwise fashion when viewed from the outside of the face

make sure you have calculated the normals for these faces correctly

I've discovered that the problem only occur when the material's MaterialType = irr::video::EMT_TRANSPARENT_ALPHA_CHANNEL