I have an issue with drawing a Texture2d in my 3d game. I followed RB Whitakers advice on changing the depth buffer, but it didnt seem to work.

The ground is supposed to be checkered. The ground is just a flat model with a texture attached to it.

 public void Draw(Matrix view, Matrix projection, Viewport viewport, GraphicsDevice device)
        {
            Matrix[] transforms = new Matrix[Model.Bones.Count];
            Model.CopyAbsoluteBoneTransformsTo(transforms);
            Matrix worldMatrix = Matrix.Identity;
            Matrix rotationYMatrix = Matrix.CreateRotationY(ForwardDirection);
            Matrix translateMatrix = Matrix.CreateTranslation(Position);

            worldMatrix = rotationYMatrix * translateMatrix;

            smoke.Draw(view, projection, worldMatrix, viewport);
            device.DepthStencilState = new DepthStencilState()
            {
                DepthBufferEnable = true
            };

            foreach (ModelMesh mesh in Model.Meshes)
            {
                foreach (BasicEffect effect in mesh.Effects)
                {
                    effect.World =
                        worldMatrix * transforms[mesh.ParentBone.Index]; ;
                    effect.View = view;
                    effect.Projection = projection;

                    effect.EnableDefaultLighting();
                    effect.PreferPerPixelLighting = true;
                }
                mesh.Draw();
            }
        }

The item smoke is what is giving me the trouble. It just draws a texture at the position of the ship. Is there something else I have to do besides changing the DepthBUffer?

Draw your smoke after setting the depth buffer. anything that uses the depth buffer needs to be drawn after its set, otherwise it can be overwritten

That made things worse. Heres the tutorial I'm referring to: http://rbwhitaker.wikidot.com/2d3d-combined

ok, so the way it looks like your code works right now, is you draw the smoke onto the screen with the depth buffer disabled, then enable the depth buffer and draw 3d stuff. this means anything else drawn on the screen after the smoke will be drawn over the smoke, no matter what the depth of the smoke is.

also, setting the depth buffer is setting a state, so once you set it, it will stay that way. i see you only set the state of the depth buffer once, which means next time around, if you haven't explicitly disabled the depth buffer, it will be on before the smoke is even drawn. if you don't want the depth buffer to be used while your drawing the smoke, you should disable the depth buffer before you draw the smoke, then enable it again after you draw the smoke (but again, it will be drawn over since it was the first thing drawn).

you can try drawing the smoke after you draw the 3d stuff, first disabling the depth buffer then enabling it again, but the smoke will always be on top of everything then. right now the smoke will always be behind everything.

Is there a way I could apply the texture to a 3D object and use that object? That may be easier in the long run

absolutely, if you want smoke in your game, you'll probably want to do it that way. texture a square (rectangle) and have the normal always face the viewer. later you can implement 3d smoke if you need.

Since I am using a type of particle system for the smoke, having 3000 of these quads on the screen would give me a huge performance issue I would think.