NURBS Texture Placement

To start, trace the curvature of a bottle and then revolve to create a bottle Mesh.

 
   

We want to place the Noble One label on the bottle as we can see on the image plane.
To do this first assign the file texture of the Label to the bottle.

- Note that the texture is distorted due to the uneven geometry created for the bottle.
- Start by changing the 2D Texture placement node
o Change the Coverage
·· U = 0.5, V = 0.5
·· Translate Frame, U = 0.5
o You should see the texture as it is on the image to the right

 
     

Now we need to use the interactive placement tool to place the label exactly where we see the label in on the image plane. To use the Interactive placement tool click on the Interactive Placement button on the 2D texture placement node and using the Middle Mouse Button click on your geometry and where you see the U and V in red click and drag to determine the coverage of the UV space over your geometry.

Careful not to drag the corners of the red outline as this will rotate the UV placement and make things look a little undesirable for this particular task.

 


We still have to modify the UV space of the placed texture. First rotateUV by –90 degrees, then change the Repeat UV, to V = -1. That should fix up the UV space placement.

Now we have the exact texture placement, we would like to create a mask for the label such that the only part of the texture that remains visible is the label. Fortunately as we already have the 2D texture placement node finely tuned for the label, we can pinch its information to create a mask.

Create a Checker texture. Delete its default 2D texture placement node and then middle-mouse drag and drop attach the 2D placement node from the wine label to the default connection of the Checker texture.

 

Change the checker black and white swatches both to black and then using the Colour balance for the checker texture, make the default colour white giving the texture swatch as seen below.


This creates a perfect mask for the bottle label. You can now use this as a transparency mask for the bottle label. Attach the checker texture to the lambert shader transparency and you will see the label appear over the bottle with a transparent bottle (see image on right).

   


The same technique as shown above is used to create a texture placement for the bottle plastic cap.

The colour comes from a coloured Phong Shader and the transparency placement was done using the same technique as above for the label placement.
Note: even though we have transparency for the lid, the specular highlights continue down the surface.
To remove them we need to have a reverse of the existing mask, and we need to map it to specular colour.


The same procedure can be done for the gold band around the plastic lid.


To bring things together we will need a layered shader.

 
Create a layered shader and apply it to our bottle.
   

Note the queue for shaders outlined in red. The far left of the queue is the outermost shader. The shader on the far right is the innermost shader. For the inner shaders to be seen, the outer ones need to have some transparency behaviour such that their underlying shaders can be seen.

For our bottle, the outer most shader will be the label, followed by the gold band, then the plastic lid and finally the glass of the bottle. To add a shader to the queue, middle mouse click, drag and drop shaders from Hypershade over to the queue. If you want to remove a shader from the queue, click on the cross at the base of the shader.

 

 

And you should have the following look for your bottle.

This is all well and good for square/rectangular labels, but what can we do if we want to create an irregular label such as that of the Perrier bottle to the right? The workflow is practically identical, the only difference being the use of a stencil node to do some chroma keying.
   
Irregular Texture Placements
 
As the label is not square, the 2D texture placement node will have trouble in creating an exact transparency mask for the layered shader.
   

The solution is through the use of a Chroma Key. When you create your label texture, make sure that the label has a background colour that is not present anywhere in the label.
In this case the colour of pure RGB blue is easy to key out.

To key out a colour in Maya we can use the stencil utility node and set its HSV Colour key to Blue.

 asdf
     

Now we just have to create a mask for the Label’s transparency.

As before we can use the 2D placement node to create a mask to make the top and bottom of the bottle transparent by pinching its placement information. Leaving us with the following.

All that is left to do now is create a mask for the remaining section. This can be done by working on the Colour balance of the Stencil node.

By making the Colour offset to zero we can make a nice mask for the inside part. Now all we have to do is add them together. This can be done using a AddSubtractAverage node and then connecting its output to the shaders transparency.

  

We will have to create another Stencil node to Chroma Key out the File image again to layer it over the transparency mask.

 

 

 

 

 

 

Finally we can create a layered shader, drop our label in first on the queue, followed by a green glass shader and we have our finished bottle (to create the cap, just do as for the wine bottle). The rendered bottle is the same as what we saw at the start of this section.