How to use the Lightning Volume Shader
NOTE: This tutorial requires SOFTIMAGE| XSI 1.5
(or higher)

Written by Ed Harriss

Take a couple of spheres and a cube

and use them to generate lightning!

Create 2 spheres and a cube. The cube is just used to provide a backdrop. It makes the lighting easy to see. (For fun, you could put an image on it, like the sky image that I've used in the example above)

Scale the cube really big and put it behind the spheres. Move the spheres apart (the lightning will strike between them.)

1. From an explorer view, set the focus to passes (a supra key).

2. Click the pass "icon" for the render pass to which you wish to apply a depth-fading effect. It's "pass property editor" will open. (In this case, Default_Pass)

3. Select the Volume Shaders tab to expose the Volume shader stack.

4. Click Add to open the file browser.

5. From the Volume folder, select the Volume_lightning shader and click Ok.

6. Select "Volume_lightning" and click the inspect button.

7. Add one sphere as a start point and one as an end point by clicking the "add" button and selecting the appropriate sphere from the menu. You'll have to do this twice, once for start point and once for end point.

8. You should now have lighting. If not move the time slider to a different frame (to see the lightning strike) Try adjusting the many sliders to create more branches, longer ones, change the angle, etc....