Preparations:

We will use an image of the Transformers logo, Cracks Brushes from Falln Stock and Texture Set from Krakograff.

Click here to download the Cracks Brushes.
Click here to download the Texture Set.

All rights of these resources belong to their respective owners.
     
 

Step 1 – Setting Up Background:

Create a document of size 750 by 550px.

Fill the Background layer with #000000.

Drag the Transformers logo to the center of the document.
     
 

Step 2 – Tracing Work Paths:

Go to View > Rulers or press Ctrl+R. While you are on the logo layer, drag a guide in and snap to center of the image.

Using Pen tool, trace a path for the left half of the logo.

There is no need to path the entire logo since the right half is a mirror of the left.
     
 

Step 3a – Forming Logo Shape:

Create a new layer above the Background and name it as logo_left.

Load selection for the path you drawn earlier.

Fill the selection with #FFFFFF.
     
 

Step 3b – Forming Logo Shape:

Duplicate the logo_left layer. Name the duplicated layer as logo_right.

Go to Edit > Transform > Flip Horizontal. You will get the right half of the logo. Position the two sides close together so you will get the full logo.

Merge both logo_left and logo_right layers. Rename this layer to logo_base.
     
 

Step 4a – Applying Texture:

Open up "the_krako_texure_6.jpg" from the Texture Pack downloaded earlier.

Resize the image so it fits nicely on the doucment.
     
 

Step 4b – Applying Texture:

Select the texture layer and go to Image > Adjustments > Desaturate.

Ctrl+left click on the logo_base layer and apply a Layer Mask on the texture layer. Rename the texture layer to base_texture.

You should be getting what is shown on the diagram.
     
 

Step 5a – Forming Inner Bevel:

Ctrl+left click on the logo_base layer to load selection.

Go to Select > Modify > Contract. Key in the value of 5px to contract the selection.
     
 

Step 5b – Forming Inner Bevel:

Create a new layer above all the other layers and name it as logo_bevel

Fill the selection with #000000 on the new layer.
     
 

Step 6 – Touching Up Edges:

Zoom in and you will notice some of the edges became rounded after the contraction done earlier.

Use Pencil tool to add in the straight edges by holding down Shift key while painting.
     
 

Step 7a – Adding Depth:

Drag the same texture in Step 4a into the document. Desaturate it and rename the layer as bevel_texture. Rearrange this layer to the top of Layers panel.

Ctrl+left click on logo_bevel layer to load its selection. Apply a Layer Mask to bevel_texture with this selection.

Select base_texture layer and go to Image > Adjustments > Brightness and Contrast. Enter -80 for Brightness and 0 for Contrast.
     
 

Step 7b – Adding Depth:

You can delete logo_base and logo_bevel layers at this point of time.

Select the base_texture layer and use Burn tool to paint in some shadows. Then use Dodge tool to paint in the highlights.

You may paint the shadows and highlights at spots similar to my diagram.
     
 

Step 8 – Gradient Overlay:

Select bevel_texture layer and go to its Blending Options.

Activate Gradient Overlay and set your settings as shown in the diagram.

Colors of gradient are #000000 to #FFFFFF to #000000.
     
 

Step 9 – Adding Glowing Lines:

Create a new layer and name it as glowing_lines.

Using Brush tool with color #FFFFFF and size 2px, paint in some lines along the edges.

Soften both ends of the lines you have drawn with Soft Eraser tool.
     
 

Step 10a – Adding Cracks:

Create a new layer and name it as cracks. Set the Blend Mode of this layer to Overlay.

Load the Cracks Brushes you have downloaded and paint in some cracks of various shapes on this layer.
     
 

Step 10b – Adding Cracks:

Try not to add too much cracks here =)

There you go! You have just done up a metallic Transformers logo on your own!
     
 

Optional:

I have added in some blue clouds and texts to complete the design.

Click here to view the final image