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- On Fri, 12 Jan 1996, Eric Gooch wrote:
-
- >
- > Ever wanted to have an invisible object throw a shadow? Object dissolve
- > doesn't work...if you dissolve the object completely, it stops throwing a
- > shadow. You can try flipping the polygons so they're invisible to the
- > camera, but still throwing shadows, but this only works at certain angles
- > in specific situations. I stumbled onto a strange technique for this
- > recently...Distance dissolve.
- >
- > Take a flat plane (ground object) and a sphere (shadow throwing object).
- > Place the sphere over the ground, and turn on Distance dissolve for the
- > sphere, with a maximum distance of say, .01. Now the sphere will always be
- > invisible, but it still casts a shadow, whether you're using ray-traced or
- > shadow-mapped lights. Weird, huh?
- >
- > For even more fun, turn on polygon edges to bright green. Now you have a
- > bright green wireframe object that casts a solid shadow. (I'll have to
- > admit I can't think of a use for that last bit, but maybe you can. 8)
- >
- >
- >
- > -Eric G.
- >
- [ ERIC...
-
- Haven't needed to do that but those are great tips to file. Thanks.
-
- Just thought I'd add, for new LW users, that if you have a solid
- object, as opposed to an animating character, and you want to save
- rendering time....AND your ground plane is flat, you can fake it. For a
- sphere, simply make a disk and set it at .0001 above ground plane. Give
- it appropriate transparency, etc. I did this in one of my first tests
- with an orange bouncing along a counter top. I also used the stretch
- requestor to have my "shadow" get larger and smaller as the ball was
- closer or farther away from the ground plane.
-
- Remeber to set you object to a null for linear travel, parent shadow to null.
- For a ship or ther such object that doesn't roll or change shape, you
- could make a specific poly that resembles the contour at the particular
- angle the shadow is cast at.
-
- Don't forget to move your shadow ahead, behind, or directly under object,
- depending on what direction your light is travelling. ( you wouldn't want
- to ave the scene backlit, with shadow travelling backwards.) ]
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- RICK CATIZONE/ANIVISION
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