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View Full Version : Propellor motion blur - Urgent!


Scott212
11-28-2006, 03:51 AM
Hey crew - I'm a bit stumped on this one. I know propellors are historically a pain in the arse, and now I see why. I've got a single blade propellor set up to spin at 6000 RPMS (physically correct, spins .25 of a degree each frame).

Setup:
Motion blur with no raytracing, Scanline: Rapid, Shutter: 0.5, Motion Steps: 15

It acts like it's not checking what's happening between frames to see the path it took. I would think spinning this fast with 180degree shutter it should be a big blurry circle, but there's hardly any blur, maybe 1/8th of a circle.

If anyone has any experience in this, I would greatly appreciate it.

~Scott

PurpleRainbow
11-28-2006, 07:38 AM
i had a same problem, in render globals - mental ray options in translation tab - performance - check export animation segments. thats all ( 15 motion blur steps is too high :) )

Scott212
11-28-2006, 08:19 AM
Excellent tip! If I may ask, about how fast was your object spinning?

PurpleRainbow
11-28-2006, 02:07 PM
as i remember i had a same spin, or something like that... :)
if image is too noisy - increase cotrast in motion blur tab....

Scott212
11-28-2006, 06:32 PM
I'm sorry, what does a 'same spin' mean?

ftaswin
11-29-2006, 02:47 AM
.....spin at 6000 RPMS (physically correct, spins .25 of a degree each frame).
~Scott


I guess....

Scott212
11-29-2006, 06:17 AM
Your probably right, I just didn't catch it cause of the wording.

kumarC
11-29-2006, 08:25 PM
Hi,
Increase the number of propeller blades and animate their rotation with a mild lag compared to the orginal baldes.creates a illusion and might work ??!!

ZippZopp
11-29-2006, 10:08 PM
unless it is something that really requires motion blur, why waste time rendering motion blur on propellers when you can just do it with a texture and save yourself the headache. Go into photoshop, make a propeller shape, put some radial blur on it. it'll give that blurred effect..put that same image as the alpha channel and now you'll have some blurred blades, just apply that texture to a circle shape....i know that doesn't address your motion blur question, but it could be a much easier solution to making propeller blades...but again, it all depends on what you're really trying to accomplish

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