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bethel
03-19-2008, 09:53 AM
We are a high school using Lightwave on these machines:

MAC G4s - 512 mb ram
Mac G5s - 2 Gb ram
Lightwave 9.3.1

Lately we are having some strange rendering issues: the scene looks Ok, but after its rendered as a QT file, it is very choppy and it skipped from the first couple of frames to the last one. Does anyone out there have any idea what is going on? Its happening to a lot of G4 computers and it hasn't happened before all year. Thanks

manproof
03-19-2008, 10:44 AM
Did this start happening after you upgraded to 9.3.1? Does this only seem to happen with the G4s? Are you rendering to your local box, or to a server? Are different people trying to write to the same location?

I don't know anything specific, so I would start troubleshooting. Try rendering a small span (20 frames or so) of the same scene on 6 different machines (3 G4s and 3 G5s.) Make sure you render to the local machine and not to a server, and that everyone uses the same output settings. Again, I don't want to suggest that there are any problems rendering to a server, I am just trying to reduce some variables.

bethel
03-19-2008, 11:00 AM
No, I upgraded to 9.3.1 sometime ago and this rendering issue only started recently. We are not rendering over the server. However, students are working as groups and sharing files via zip disks. We've tried rendering on different machines, no change. I experimented with one of the problem scenes by first, saving all motions. Then, I started a fresh scene, reloaded all objects and their motion files. It rendered fine. I'm going to try this on some another scene to see if its consistent. Thanks for your input.

manproof
03-19-2008, 12:19 PM
Glad to hear it's going better. If you can pinpoint the problem it may be useful to share what the cause was. Good luck.

RonGC
03-19-2008, 01:37 PM
Maybe a good idea would be to share this with Chilton, the NT in house Mac coder. Just a thought.

Ron

Chilton
03-19-2008, 01:49 PM
Hi Bethel,

I think the general consensus among 3D artists is that you should always render to images first, and assemble them (into movies) in another program.

But, if you can reproduce this, and you don't mind sending me a copy of the files, I'll gladly take a look.

[email protected] or [email protected]

Thanks!
-Chilton

bethel
03-20-2008, 08:06 AM
Unfortunately, we don't have software for post-rendering except for iMovie. I purchased After Effects over year ago for a couple of machines. But, can no longer afford it due to budget constraints. I did render a couple of scenes over on a different machine, and it worked. I'm going to try to re-render all the scenes we have issues with over and find out if it works on a different machine. Thanks!

Chilton
03-20-2008, 09:17 AM
Hi Bethel,

I think QuickTime Pro ($29) is what many people use for this. That said, we're changing a few things related to QuickTime on the Mac in 9.5, so if you can get me a scene or instructions for reproducing this, I can make sure it gets taken care of.

-Chilton

JeffrySG
03-20-2008, 09:27 AM
^yes, QT Pro works great for this! :)

bethel
03-20-2008, 10:07 AM
I have QT Pro. Have never tried to use it for post processing. How would I go about doing that, for instance, if an animation consists of 100 frames, do I load one at a time and then combine each frame? Thanks!

BeeVee
03-20-2008, 10:11 AM
You can even use LightWave to do it. Here's how: http://www.lightwiki.com/Using_LightWave_to_compile_animations

B

bethel
03-20-2008, 10:20 AM
OK, but if it rendered choppy and frames are being skipped during a regular render, would it be any different if these same frames are reloaded and rendered as an image sequence? I'll try that though. Thanks for the info.

bethel
03-20-2008, 10:21 AM
I am rendering another animation on a different computer. If this doesn't work, I'll send you the files. Thanks a lot.

Sean Martin
03-21-2008, 10:41 AM
For some reason I have never been able to get smooth playback when rendering straight to Quicktime from lightwave.

However when saving stills or image sequences and then loading them into Quicktime I seem to get a smooth playback.

Don't ask my why but its seems more successful?

also you can render the frames that you want and stop and start when you need to.

Load image sequence in Quicktime

eblu
03-21-2008, 11:57 AM
this seems to me, bethel and Sean Martin,
to be a compression related issue.

Quicktime gives you several options on a Per-codec basis for saving movies. So it can get a little complex, but basically, I think your Lightwave rendered Movies are too big, and your quicktime generated Movies, are better.

playing back a file thats to big, will result in choppy motion as the computer tries to keep pace with the movie by skipping frames.

what is Most likely happening is that you have too many "key frames" In the movie. What is a key frame? Is it the same thing as in Lightwave? no. it is not. Quicktime saves time and resources by drawing Only what has changed in each successive frame. Things that don't change are left alone. This can lead to terrific savings in drawing time and system resources. Once in a while, everything changes in the picture, and Quicktime has to draw the whole frame. This is a Natural key frame. You can set Quicktime to generate key frames, frames in the movie where the whole picture is drawn, at a pace. for instance every 240 frames, every 30 frames, every 1 frame.

if this key frame value is set to draw a new key frame every 1 frames... then the resulting movie is going to be enormous, regardless what kind of codec you use.

so in the quicktime options panel which you can get to whenever and wherever you make a Quicktime movie file, you need to look for the key frame options. they are usually radio buttons named :
automatic
every (with a text box)
all

automatic is a good option.
you can also select every and put a High number in there. like 300 or 1000
do not set "every" to 1 or 2, or 10.
key frames are basically unnecessary these days.
do not do all.

the quick way to test to see if I'm right, get quicktime pro, open one of the choppy movies, and export it... making sure to change the key frame settings, and see if the exported movie will play better.

But, I suggest for your use, you render LW to Image sequences, and then create Quicktimes from the renders. there are many benefits from rendering to an image sequence.

bethel
03-22-2008, 10:49 AM
Wow, thanks for this great info. I can't wait to get back to school on Tuesday (we have a 3 day weekend) to test it out. Thanks again, and have a wonderful weekend!


this seems to me, bethel and Sean Martin,
to be a compression related issue.

Quicktime gives you several options on a Per-codec basis for saving movies. So it can get a little complex, but basically, I think your Lightwave rendered Movies are too big, and your quicktime generated Movies, are better.

playing back a file thats to big, will result in choppy motion as the computer tries to keep pace with the movie by skipping frames.

what is Most likely happening is that you have too many "key frames" In the movie. What is a key frame? Is it the same thing as in Lightwave? no. it is not. Quicktime saves time and resources by drawing Only what has changed in each successive frame. Things that don't change are left alone. This can lead to terrific savings in drawing time and system resources. Once in a while, everything changes in the picture, and Quicktime has to draw the whole frame. This is a Natural key frame. You can set Quicktime to generate key frames, frames in the movie where the whole picture is drawn, at a pace. for instance every 240 frames, every 30 frames, every 1 frame.

if this key frame value is set to draw a new key frame every 1 frames... then the resulting movie is going to be enormous, regardless what kind of codec you use.

so in the quicktime options panel which you can get to whenever and wherever you make a Quicktime movie file, you need to look for the key frame options. they are usually radio buttons named :
automatic
every (with a text box)
all

automatic is a good option.
you can also select every and put a High number in there. like 300 or 1000
do not set "every" to 1 or 2, or 10.
key frames are basically unnecessary these days.
do not do all.

the quick way to test to see if I'm right, get quicktime pro, open one of the choppy movies, and export it... making sure to change the key frame settings, and see if the exported movie will play better.

But, I suggest for your use, you render LW to Image sequences, and then create Quicktimes from the renders. there are many benefits from rendering to an image sequence.

JeffrySG
03-24-2008, 08:11 AM
QT Pro has the Open Image Sequence, in the file menu. Just select the first frame and tell it what the fps is.... then you can export it with whatever codec you want, or play it right there (uncompressed) or step through the frames.

If every frame is different than you know it rendered correctly. Plus you get to try different codecs and compression levels without losing quality.

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