Illuminate only specific areas in a render

Author: adorana

Tools Needed

• Poser 5 or 6
• A graphic program

This tutorial shows you how to set a light with a self-created image map for illuminating only certain parts of the render. You can paint the areas manually or select the whole figure in the scene like shown in this topic.

First you create your scene. For showing the effect, I use a simple scene with one figure and only one light from above. This light should only shine on the certain areas we like it to.

You change into the Shadow Cam of the light and activate the light properties with the menu at the bottom of the document window. Now you can see the Shadow Cam and change the light parameters. Each change can be seen in the camera.

Set the zRotate Value to 0 and adjust the xRotate and yRotate values until the object (Victoria) is in the middle of the window.

If your image hasn't a square form, temporary set the width and length to the same value. We will later use the rendered image as a map, and the square form fits better.

Render the Shadow Cam View with only 'Smooth Polygons' selected and save your pic as a TIF-file.

Open your render in a graphic program like Photoshop. Go to the Channel Panel and with pressed Strg-key click on the Alpha Channel. Victoria's silhouette is now selected.

Fill the selection with white, invert the selection, and fill the new selected area with black and save the file with a new name.

Naturally it would also be possible to paint the desired areas manually instead of filling a selection.

Back in Poser, select the light in the material room. Plug your new image into the Color and Intensity of the light and change the following parameters:

U_Scale = 0, 5

V_Scale = 0, 5

U_Offset = 0, 25

V_Offset = 0, 25

Image_Mapped = None

Background = Black

If you don't like the volumetric effect, you can omit this step.

I'd like to show the effect with a volumetric light, so I need a background. I load the DAZ3D Multiplane Cyclorama and set the material to a simple white.

Activate 'Volume_On' in the Atmosphere material in the material room and set the 'Atmosphere Strength' in the light properties to 1. (I also changed the Volume_StepSize to 0, 5.)

Now you can render…

You see – only the areas that were visible in the ShadowCamView were hit by the light. The others lie in the dark. The light beams perfectly touch the arms of Victoria.

(Rendered without cast shadow to show you the image on the floor!)

I hope this tutorial was useful for you!

To use the new robot eye, import your character into Bryce. Ungroup it, delete one of the eyes, and then add your robot eye. Just scale and reposition it till it fits in the old eye's area then regroup everything. Lower the lighting a bit and you will have the great effect you've been looking for.