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cesario1212
09-16-2003, 04:31 PM
Hey all, I was wondering if any of you Mac people have had issues with the spinning light trick in LW? Everytime I render with just low anti-aliasing, my lights never "spin" to fake the radiosity. If I put on dithered motion blur instead of normal MB OR I just bump in up to medium anti-aliasing (with normal motion blur still on), my lights then spin.

Low anti-aliasing with normal motion blur works for the spinning light trick on the PC. Anyone have a clue why it's not on my mac?

My rig is 12 lights total, 3 lights per side in a dome formation.

Art-man

Julian Johnson
09-17-2003, 02:54 AM
I think it must be something scene specific either to do with the rotation angle of the rig or the motion blur length. Here, with 7.5c, a single spinning light set to Low AA and Normal Motion Blur 'spins' the lights properly...just as it does on a PC. Have you got any more specifics on your scene or could you post just the rig somewhere?

Julian

cesario1212
09-17-2003, 03:27 PM
I'll post a few scene files if I can. I've only gotten the spinning lights to work on a few scenes, but I can't make a out a pattern yet.

I've been using the trick fine on PC's for a couple years now. I know my motion blur and rotation settings are correct.

Art-man

cesario1212
09-17-2003, 03:39 PM
Here are a few scene files and the objects for them so you can run a test if you want.

Enjoy.

Art-man

cesario1212
09-17-2003, 03:49 PM
Okay, so for whatever reason, the files didn't go through on the last post, so here is another attempt.

Art-man

cesario1212
09-17-2003, 03:55 PM
Okay, so for whatever reason, the files didn't go through on the last post, so here is another attempt.

Art-man

cesario1212
09-17-2003, 04:04 PM
Here's part two if it works

Art-man

----------------
Nope, it didn't work. I think it's too big.

Julian Johnson
09-18-2003, 03:20 AM
Hi Art-Man,

I took a look at the 'Shot12_Zed' scene and did the following:

Stripped out the key and fill light rig so that all I had in the scene was the spinning rig. Set ambient to 0.

Set the light intensity for all the lights on the spinning rig to 20%.

Placed a test object (ball on plane) at the centre of the rig.

At Low Antialiasing with Motion Blur the 5 rotation steps for each motion blur pass seemed to put the shadows on top of one another so I had five equally spaced shadows of the ball radially placed around the ball (the fifth pass is layered on top of the first).You can see the motion blur stepping at the edge of the shadows. isn't this all you can expect since you only have four effective samples of your shadows to cover 360 degrees and four columns of evenly spaced (and relatively hard edged) light?

When I tried the same scene on a PC, I got the same results.

As soon as I upped the Motion Blur to dithered I got another 4 passes which 'filled in' the non-shadowed areas and gave a much smoother result. Again, this was identical on the PC.

I duplicated the spinning rig and offset its heading so that I had 8 evenly spaced columns instead of four and it started to fill in the gaps left by Low/Normal and gave a result that was similar to dithered. Similarly, increasing the cone angle and fuzziness of the spots helped to spread the shadows into one another at the Low/Normal setting.

So far, can't find anything that differs from the PC version of Lightwave. Am I doing something wrong in the way I've setup this test?

Julian

cesario1212
09-18-2003, 09:36 AM
Interesting. Nope, you're doing nothing wrong. I'm just not getting any kind of spin when I render the scene files. They all render in the same place instead of just part 1 and part 5 doing so. Hmmmm. Weird.

I'll try the cone angle idea and offsetting the lights more.

I'm just wondering why, at least on my computer, it works in a few other scene files and not the others (no matter what the light intensity).

Will you try a subpatched object for me with a level 3 division? Give the object before subpatching a decent poly count...like 1,000 or slightly more.

Thanks for your help!

Art-man

Julian Johnson
09-18-2003, 12:57 PM
Art-man - I tried a subpatched object (base polys 1300/level 3 subpatch in Layout) but it made no difference to the overall effect. I'm not sure what to suggest. The only thing I noticed in the scene I tried was that the cumulative light intensity of all the lights in the spinning rig was only 24 (each being set to 2) which seemed a wee bit low to me but I didn't have any of the original objects to really understand where the lighting was going...

- Julian

cesario1212
09-20-2003, 11:34 AM
Eki form Eki's plugins discovered something interesting. Since the angle of separation of the lights is close to the angle of movement from each pass on low AA, the spin effect is not showing up. I tested his theory and equations, and voila. My problem is that my lights are too evenly spaced, at least for low AA on normal motion blur. Go figure.

Art-man