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The blog has been online for more than 4 years and there’s still not a single post even remotely related to the delicious brew called coffee… Perhaps it will someday, but in the meantime you can read the articles about Softimage. Most of the material are tutorials and Q&As I’ve written for 3D World Magazine sometime between today and 2003. If you have any questions please don’t hesitate sending me an email.

Thanks to Letterbox Animation Studios for hosting all the scene files.

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Sunday, February 8, 2009

Cast Shadow Only Lights in XSI

Step 01
Using two lights
While it may sound simple enough, it does require a little trick. By adding a light to the scene you’ll get the wanted shadow but you’ll also get the extra illumination. So you’ll need to create a second light that will remove the added illumination but leaves the shadow intact. Open the scene NegativeLight.scn from this issues CD.

Step 02
Creating the shadows
The scene consists of a couple of dummy objects and the default lighting. From the Primitive > Light menu choose Sport to create a spotlight. In the spotlight’s PPG scroll down to the Shadow section, check the Enable checkbox and set the Umbra to 0 (zero). Now, position the spotlight so it cast shadows in the desired direction.

Step 03
Removing the extra illumination
With the spotlight still selected, press [Ctrl] + [D] to duplicate it and open the PPG for the new light. The natural choice would be to change the intensity of the light. However, XSI doesn’t allow negative values for the Intensity. Fortunately it does for the RGB colors. Set the R, G and B to -1 and uncheck the shadow checkbox. Remember to move both light if you want to alter the direction of the shadow.

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