View Full Version : What's My Line

Richard Hebert
01-20-2012, 05:12 PM
Hi Guys,

Lines are driving me nuts and can't figure out if this is user error (probably) or software bug. I'm getting what looks like geometry lines showing up when I render an object with bones and photoreal motion blur. I'm only using one pass of blur (comparing render times with MB passes vs. more AA passes) and increasing AA to about .025 adaptive sampling. In other renders using objects without bones I'm not getting these artifacts. No bones = no lines in motion blur render of 'hard' objects. They only show up when deforming with bones or joints. Any thoughts? Thanks a bunch guys and gals!


01-20-2012, 08:06 PM
I've never seen that.
Motion blur works diferently depending on the camera type, so try classic, it is known for good and fast motion blur, or do motion blur in post like I do with ReelSmart by RE:Vision.


Richard Hebert
01-20-2012, 10:38 PM
Reel Smart sounds good but will not well with a helicopter that will appear in the shot. The rotors won't blur properly. I'm going to look into the camera though. Thanks for the direction.


01-21-2012, 07:03 AM
First off, you appear to be using a tiny amount of blur, there's certainly no large moves, so i cant help but wonder if there's any point in rendering such a small amount of blur. Second, its not only the poly appearance on the shirt, the side of the head, and other areas dont look right at all. Makes me think that there's something wrong with your geometry itself... doubled up polys/doubled up object, I dont know.

As for things like helicopter blades, these are also a pretty wasteful use of motionblur... you'll get a far quicker render by creating a blurred rotor texture, and mapping this to a disc in the rotor position. Itll give you more control over blur amount, the strobing effect you get, and so forth.

Richard Hebert
01-21-2012, 08:17 AM
Great tips but still need to know what's going on with the deforms and blurring. Multiple passes of 5 or 6 tend to reduce or remove this effect but how or why is it happening at all is the question. Does this happen in LW10 or 11? There are no large movements in that particular frame but he does go running in the sequence.


01-21-2012, 09:45 AM
Hi Richard,

I had exactly the same problem in 2 projects we were recently involved(LW9.6 & LW10). The only difference is that I was using an MDD to deform the character as the animation was done in Maya. I tried everything to solve it but it was always there. I always thought that it had something to do with the MDD.

Sadly the only solution I found was to render with Classic camera/traditional motion blur.
Im sure if you try that your lines will disappear. However this is a major bug which will become a bigger problem if the next version of LW excludes the classic camera.

Hope that helps,

Richard Hebert
01-21-2012, 01:53 PM
Hi Antonis,

I can still render with the real lens camera but it has to be in several passes of Motion Blur. If I do this, the problem isn't apparent even with very little or no motion on the object. The problem is a nuisance because it's jacking around the render times unnecessarily. If blurring is OK using 1 MB pass and .05 Adaptive Sampling... can't use it because the lines appear. I can't even tell you why I prefer the real lens camera. I have noticed the effect with the perspective camera as well though. I haven't exhausted every avenue but like you said what happens when the classic camera goes to the museum... then what? Maybe that's when the problem will be looked into (or glossed over as usual). Thanks for the tips all. I'll post any discoveries.