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View Full Version : Help With Motion Blur Please!



BlackOpsBen
10-20-2005, 11:14 AM
I am making a scene for my movie where a ship comes out of slipspace. I have antialiasing on and motion blur set to 100% but whene I render it there is no blur. The camera is stationary while the ship flies on screen. Shouldn't it be working, or am I doing something wrong?!? Help!

toby
10-20-2005, 11:30 AM
Is it possible that you're not seeing the blur because the ship isn't moving very much? Can you tell us your exact settings, and post images with and without motion blur?

If you want to see streaks behind the ship, use more motion blur, like 300%. You'll probably have to use extreme AA as well.

BlackOpsBen
10-20-2005, 12:20 PM
Okay, here are my settings (it is a huge scene!):
Grid size: 500mm
Camera location: X:1.1404m Y:1.5m Z:-2.9944km
Ship Initial Location: X:75.2859m Y:1.3939m Z:-3.1576km
Ship Location after exiting slipspace (5 frames later): X:1.6382m Y:1.3936m Z:-2.9959km
After that it goes at a much slower speed. As you can see it is obviously going incredibly fast. It covers about 1577m in about 0.16 seconds.

Oh great! I just ran into another problem as I am typing! When I use Antialiasing PLD, I see my ship but no blur. When I use Classic Low, I don't see the ship AT ALL, only the stars in the background! AHHHHH
HELP!

Captain Obvious
10-20-2005, 03:32 PM
Chances are the ship just passes by the camera without ever appearing. Lightwave's motion blur works in a rather interesting fashion. Instead of taking random samples and causing noise, it simply renders the anti-aliasing passes at different times. For example, frame 1 with motion blur might be frame 0.5, frame 0.6, and so on, up to frame 1.0. But if the ship moves too darn fast, it might not appear in any of the subframes, and you don't see a thing. If it appears in only one of the subframes, it will not be blurred. The blur occurs when you have multiple passes closely together, so it looks blurry.

Turn off all raytracing and render using PLD 35-pass and dithered motion blur (for a total of 70 passes, it takes a while to render to say the least). If it still doesn't appear at all (or at least not blurred), something else is wrong.

BlackOpsBen
10-22-2005, 02:56 PM
Thanks for your tips. That wasn't exactly the problem though because the ship is flying towards the cam so its always in view. The problem turned out to be that the motion blur was set to 100% so it was trying to "stretch" the ship across a HUGE distance so it became virtually transparent.

Captain Obvious
10-22-2005, 06:16 PM
That makes sense, too!