In order to create 3D lettered signs in lights, you will need to first create an object. Open Illustrator. Type your letters on the page. Adjust the font to the style you would like. Click on "effect". Then, click on "3D". This will allow you to rotate the image for the angle that you will want to see it at.
Click on "object" and "expand". This will give it depth. Then, copy and paste it to Photoshop. Click on "edit" and "transform". This will allow you to stretch the image. Next, you can use custom colors to color it. Color the front facing image first. Next, add a darker tone to fill the recess areas. Next, make the bottoms of the figures a different shade all together. Continue to add layer and dimension of color. You can use the burn tool to darken certain areas. Continue contouring. Next, you will need to hollow out the center, in order to add lights. If it is necessary, you can enlarge areas to make it more visible. Draw little circles. Then, fill it with a yellow from your custom colors. Add a filament detail and a hot spot to it, which is a white area. Adjust the inner style, giving it an inner glow. Save it as a design pattern. Next, use "fill" to fill the letters with light bulbs. You can adjust the scale of your light bulbs. Skew the bulbs: "transform and rotate". Adjust the color and tone.