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Ty Catt
01-20-2010, 06:37 AM
Hey y'all,

I have a scene with a moving camera and lots of glass in it (glass objects, not windows) and for obvious reasons, the render times are a killer. And that's without the dielectric surfacing node.

I am not that fluent in baking, but is there a baking solution that would cut down on render time? I thought I understood baking years ago, but it seems to have developed more over the last couple LW versions that I lost touch and am now confused (I needed to take a nap after I found out you can bake motions in rigging).

I have been searching the forum for a definitive bible on current baking, but haven't quite found one yet. The LW manual is more on the how to rather than possible baking uses.

Thank you!

Tyler

3DGFXStudios
01-20-2010, 06:44 AM
to speed up you rendering you can do a couple of things. First exclude all the glass surfaces from the GI (finalgather or MC radiosity (don't use MC It will take a lot longer) Don't use the volumetric radiosity option and turn of the transparency in the "GI render window". Not the ray-trace options. Those need to be enabled. Than you can bake you radiosity to a file with the cache option.

And if you want to know how things work read this: http://www.except.nl/lightwave/RadiosityGuide95/index.htm

Ty Catt
01-20-2010, 07:05 AM
Thanks,

I've read Except's link. Hell, I've printed it and carried it around for quick reference. But I don't even have radiosity enabled yet!

But I still need to understand fully how baking works and if it would help in the speeding up of the rendering.

Or are you implying I can only bake if radiosity is enabled?

Sorry, still slow on baking...

Thanks,

Tyler

3DGFXStudios
01-20-2010, 08:21 AM
You can also bake textures but that's not what you want here. That's more designed to bake lighting in textures for games etc. You can only bake radiosity when it's turned on. Do you use lot's of lights? Area lights are slow so use as few as possible..

What are your render settings?

Ty Catt
01-20-2010, 09:28 AM
Thanks for your help.

I gotta roll to job now, I will post the settings soon!

Thanks again,

Ty

3DGFXStudios
01-20-2010, 09:29 AM
ok np ;)

toby
01-20-2010, 04:50 PM
You can't bake any reflection or refraction, that's what's taking so long right? You can probably get away with a lower ray recursion than the default 16, and that will save lots of render time. Try a setting of 3 to 8.

biliousfrog
01-21-2010, 05:18 AM
It would also be useful to have some stats for the scene and the render times...if you're rendering to HD with millions of reflective/refractive surfaces then it's going to take a lot of processing but your idea of 'long time' might not be as much as some.

Ty Catt
01-21-2010, 12:18 PM
Thanks everyone,

Too bad about no baking (or is it? :D Like I said, baking is still pretty foreign to me).

This project is vaporware development for a medical supply company and I can't share too much.

I can tell you that:


It's only gonna be rendered at SVGA (or possibly XGA)

I have my Recursions set at 4

The polygon count is under 300,000

Perspective Camera, Box RF and Fixed SP, AS with 0.1 threshold

I have Final Gather- interpolated 80% - IB=1 - RPE=64 - AT=45 - MinPS=4.0 - MaxPS=100 - Mult=50%.

Render times aren't too long at a low AA, but the client likes the look and wants more of the glass feel applied to more objects. And not to mention the final render will have to be at a higher AA and possibly better GI settings.

Overkill? Am I missing something?

Or just suck it up and stick it out?

Thanks, comrades,

Tyler

toby
01-21-2010, 04:03 PM
Those frames shouldn't take very long at all, what are your times? If this is animation the radiosity will probably flicker though.

Danner
01-21-2010, 05:16 PM
1. make sure only the glass that needs refraction has it on.
2. make glass single sided when ever possible.
3. play around with antialias settings, I tend to vary them A LOT from scene to scene.
4. turn off motion blur. do it in afterfx or dfx in post. with ReelSmart Motion Blur
5. if nothing is moving on your scene except the camera.
a. turn your radiosity multyplier to 100%
b. turn cache on. if it's not.
c. give your radiosity cache a name.
d. do a bake radiosity pass with a 10 frame interval.
c. Lock your radiosity.
d. then rerender the scene.

The multyplyer is evil for animation, good for stills only. takes longer and longer as the scene progresses.

pleas excuse my total lack of spelling an punctuation, it's late =)

biliousfrog
01-22-2010, 08:11 AM
I agree with toby, it doesn't sound too bad but it depends on what you're rendering with. My recent architectural animation (here) (http://www.newtek.com/forums/showthread.php?t=105363) had over 8.5 million polys, loads of glass, trees, plants, cars, multi-bounce GI, 1280x720...took about 10 minutes per frame on a i7 920. You should be able to get much better even on a slower system, 5-10 minutes max.

Ty Catt
01-22-2010, 08:48 AM
Thanks Danner and Toby for the suggestions.

Testing them as we speak.

Bilious- Jesus, wish I had the skills (and clients) you had with that project. MOST IMPRESSIVE!:thumbsup:

My renders at SVGA 800 X 600 using the previously posted settings are coming out to 13 minutes!

Seems odd with your million poly render time.

I know that even 13 min. isn't the end of the world, but like I mentioned, I was plannning on upping the ante on AA and GI settings. And the anim is shaping up to be 250+ frames

That's what made me freak out a bit.

Thanks!

Tyler

biliousfrog
01-22-2010, 09:42 AM
Have you tried turning off AS, using classic reconstruction and classic SP and then upping the AA? You could also try using an oversample value of 0.5'ish to soften things a little...Adaptive sampling can be a help or a hindrance, I dropped it completely with that animation, it was adding too much with no noticable gain.

Ty Catt
01-22-2010, 10:02 AM
Got it!

I'll give that a try, too.

Thanks for all your kind assistance!

Tyler

Ty Catt
01-25-2010, 09:10 AM
Bilious,

You were dead on- turning off AS and changing back to classic cut the render frame IN HALF!

Thanks again for all your suggestions and help!

Tyler

Danner
01-25-2010, 01:05 PM
Yeah antialias is very scene dependant, sometimes it works better with AS sometimes it doesn't. I look for a trouble spot and do a buch of quick tests with limited region on and play with passes, AS, treshold, oversample, I often turn AS off and switch to box reconstruction.

If your scene has panes of glass, like tables or glass doors, give the edge of the glass a darker non transparent, but reflective surface. Looks more natural and renders faster.

Other things to try: use as few lights as possible. and the ones that you do use, exclude the objects that won't benefit much from them. Also look hard at each object if possible and see if you can turn off self shadow, cast shadow, receive shadow. For example, walls don't need to cast shadow unless you have sunlight coming from the outside, (but might need to self shadow) and the floor doesn't need to self shadow or cast shadow. Little things like that can add up. My latests scenes are arch viz interiors that render under 2 minutes in HD using radiosity. :hey: