Motion Blur Advice

jlwolff · 11-21-2009, 01:19 PM

Hi, everybody - a junior lightwave artist seeks advice from those with experience...

I have a transformation scene in my current project. Character is in a high speed spin while the camera does a counter orbit. What kind of motion blur settings should I be using? (we're rendering with 9.3.1, btw)

When I was hired to complete the project, we were already a week behind deadline. As much as I would like, I don't have the time or resources to make dozens of test renders, so if someone could help me ballpark this, I'd appreciate it.

Thanks!
JL Wolff

UnCommonGrafx · 11-21-2009, 01:34 PM

Update to 9.6 and use the viewport motion blur abilities to gauge what you need. Only the Amazing could tell you what you need, sight unseen.

Captain Obvious · 11-21-2009, 01:35 PM

I'd recommend using the standard 50 % blur length settings, if you want 'realism'. It usually looks alright. Just make sure you have enough anti-aliasing.

shrox · 11-21-2009, 01:40 PM

Upgrade, it's free.

jlwolff · 11-21-2009, 01:48 PM

Quote:

Originally Posted by UnCommonGrafx

Update to 9.6 and use the viewport motion blur abilities to gauge what you need.

Oh, if only I could.

But I came onto this project late and with little say as to the initial setup. 9.6 throws off at least one of the rigs just slightly

...but if I set it up in 9.6 and then export it back...

Thanks, Robert.

Quote:

Originally Posted by Captain Obvious

I'd recommend using the standard 50 % blur length settings, if you want 'realism'. It usually looks alright. Just make sure you have enough anti-aliasing.

Thank you, Captain. That's very reassuring.

jlwolff · 11-21-2009, 01:57 PM

Quote:

Originally Posted by shrox

Upgrade, it's free.

Yeah, I'm not entirely sure why the previous project lead was so set on using 9.3, but I'm kinda up against the wall here and I feel I have enough to worry about without adding compatibility issues into the mix.

Captain Obvious · 11-21-2009, 02:30 PM

Lightwave's motion blur is very solid: there are very few motion scenarios that it can't cope with. Rotation, parenting, etc, it can cope with all of it.

Mr Rid · 11-21-2009, 05:03 PM

Use Classic Camera with 'Enhanced Insane' AA, and classic blur. Dithered blur takes a lot longer, doesnt usually help much, and may introduce edge problems in comp. I find that decent photoreal blur settings usually take way longer and may only be necessary for subjects moving extremely fast, or when rendering DOF. May test by doing a limited region F9 on a small portion of your subject, at a frame with max motion.

Captain Obvious · 11-21-2009, 05:16 PM

The OpenGL preview is a very close replication of motion blur rendered with classic camera. If you set the OpenGL passes to, say, extreme and do a test and it looks fine, the render should look fine too.

shrox · 11-21-2009, 05:38 PM

Upgrade. Tell the client Lightwave 9.6 has more cowbell.

jlwolff · 11-21-2009, 06:49 PM

Thanks, everyone. You've been really helpful.

Mr Rid · 11-21-2009, 07:53 PM

Quote:

Originally Posted by Captain Obvious

The OpenGL preview is a very close replication of motion blur rendered with classic camera....

Hmm, the one time I tried that long ago (probably v7.5) I remember it being wonky. I just tried it again and am still getting wonkyness. It became stuck on continuously and I could no longer move objects... I start a new scene and I just got this

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The third time I set up the scene it started working correctly.

But if you want to check different setting tweaks, viewing the edge of an object in the alpha channel is a precise way to see what blur and AA is doing.

Ok, how do you turn GL moblur off?

Another weird thing in my display-

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Cageman · 11-22-2009, 06:12 AM

Quote:

Originally Posted by Mr Rid

Ok, how do you turn GL moblur off?

At the same place where you find Bone XRay, Bone Wight Shade and HeadLight. It is called DOF/MBlur Preview (the arrow down icon next to the OGL shading dropdown for the viewport).

Also, if you bring up Preferences-Display (shortcut key = d), at the very bottom of that window you have something called DOF/MBlur Preview Passes. The default is 9. Change it to something like 3 will make it much faster, but looks worse but can still be a help, or if you are going on lunchbreak, you can crank it up to 35 (which is max) and make a preview.

EDIT: Also worth knowing is that the OGL Mblur/DOF is based on your camera settings. So, if you have a camera with DOF and MBlur enabled, and you want to work with DOF in OGL, you have to temporarily turn off MBlur (just turn it off on the camera) so you can get a clear picture of what the DOF does alone.

Cageman · 11-22-2009, 06:48 AM

Quote:

Originally Posted by Mr Rid

Use Classic Camera with 'Enhanced Insane' AA, and classic blur. Dithered blur takes a lot longer, doesnt usually help much, and may introduce edge problems in comp. I find that decent photoreal blur settings usually take way longer and may only be necessary for subjects moving extremely fast, or when rendering DOF. May test by doing a limited region F9 on a small portion of your subject, at a frame with max motion.

Depending on what you have in the scene, a combination of AA, AS and just 1 MBlur pass can greately speed things up compared to using Classic Camera or classic mblur. You also have to factor in that the new cameras are optimized for raytracing and have much better multithreading capabilities compared to Classic Camera.

For example, in many cases I can use these settings and get a very good result within a fraction of the time it would take classic camera to produce the same:

AA:1
AS: 0.03
OS: 0.1
Mblur: Photoreal
MBlur Passes: 1

Playing with AS setting (lower the better quality), I can make the mblur and/or DOF very smooth and good looking, but still renders way, way faster compared to classic camera settings.

But as always, it is a trial and error process to make use of the more advanced settings in LW and sometimes it is better to stick to the production proven solutions.

Mr Rid · 11-22-2009, 11:32 AM

Quote:

Originally Posted by Cageman

...
For example, in many cases I can use these settings and get a very good result within a fraction of the time it would take classic camera to produce the same:

AA:1
AS: 0.03
OS: 0.1
Mblur: Photoreal
MBlur Passes: 1

Playing with AS setting (lower the better quality), I can make the mblur and/or DOF very smooth and good looking, but still renders way, way faster compared to classic camera settings....

I am trying your settings on a blank sphere, and when I flip over to Classic Camera with Enhanced Extreme it is rendering in less than half the time and has slightly smoother moblur(?).

Quote:

Originally Posted by Cageman

At the same place where you find Bone XRay, Bone Wight Shade and HeadLight. It is called DOF/MBlur Preview ...

Thanx, I had finally found it in the Configure Keys menu (overnamed 'Interactive Depth of Field/Motion Blur Preview') and assigned a hot key. I dont know why it's not in a logical place like the OpenGL prefs. I never had a use for this in GL, but I keep getting weird things in the display.