Translucent Shading

The Translucent shader in 3ds Max lets you simulate substances that allow light but not clear images to pass through. An example of this is the type of screen on which slides and movies are projected. In this short lesson, you'll use the Translucent shader to set up a projection screen where on its back surface you can see the image being projected as well as the shadow of an object between the projector and the screen.

All the files necessary for this tutorial are provided on the program disc in the \tutorials\materials_and_rendering directory. Before starting the tutorials, copy the \tutorials folder from the disc to your local program installation.

Load and render:

1. Load the file tut_translucent_shader_start.max. This is located in the \tutorials\materials_and_rendering folder.
2. Activate the Camera02 viewport and render the scene.
   In the rendered image, you can see an image being projected onto a screen, with a cutout of a person walking in front of the projector casting a shadow onto the screen.
3. Activate the Camera01 viewport and render the scene again.
   From this perspective, you can see the rear of the screen, but no image or shadow appear on it. You'll make the scene look more realistic by applying the translucent shader.

Change the shader:

1. In the Camera01 viewport, select the Screen object, and press the M key to open the Material Editor.
2. In the Material Editor, look at the fourth sample sphere, at the left end of the second row.
   The material is selected. Its name is Screen, and you can tell that it's applied to the selected Screen object because of the solid white triangles in the corners.
   Currently, the Screen material uses the Blinn shader, which is the default shader used by the Standard material.
3. On the Shader Basic Parameters rollout, click the drop-down list (where “Blinn” appears) and choose Translucent Shader.
   The name of the second rollout changes to Translucent Basic Parameters and a new Translucency group box appears at the bottom of the rollout.
   You control the degree and color of translucency with the Translucent Clr (Color) setting. By default, this color is black, which effectively turns off translucency.
4. Click the Translucent Clr color swatch, and use the Color Selector dialog to set the Value to 174.
   By using a shade of gray, you change the translucency amount while maintaining a neutral tone for the translucent material.
5. Close the Color Selector dialog, and then render the Camera01 viewport again.
   Now you can see the projected image and the shadow from the rear.
   You can load this version of the scene from the file tut_translucent_shader_finish.max.
6. Try setting different colors and values for Translucent Clr, and render each time to see the difference. Also try setting different colors for the material's Diffuse and Translucent components, and rendering from the front and back.
   The translucent color has no effect on the diffuse color, and vice-versa. For realistic results, use the same colors for both.

Summary

You learned how to work with the Translucent shader and use it to simulate the effect of an image shining through a projection screen. Other types of objects exhibit translucency as well, such as plastic and frosted glass. See if you can model such an object and give it a realistic look with the Translucent shader.