What can I do to make Lightwave render faster?
The possibilities are so numerous they're hard to keep track of!

Lately some animators have been asking me what they can do to bring down their render times. Some of the answers are not obvious to the novice. I'll try to list some here in an order that I feel is most likely to help. This is a work in progress, so if you have any questions, comments or suggestions, please contact me

ABSTRACT:

The way to get your renders out faster is to limit and reduce the demands on your systems resources. Everything you do from the point you log in will likely have some impact on how fast your final render goes. Anything you can do to increase available memory and CPU time will reduce your render times.

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METHODS:

Reboot!

Many programs leave behind "tasks" for house-keeping. Worse yet, many poorly written programs "leak" memory by requesting it from the system, but forgetting to free it. Over the course of normal usage, the system RAM may get very cluttered and limited. Save your work, and then reboot. In the past I've seen render times drop up to 30% just by rebooting! Individual results will vary of course.

Create a 'Render' environment

Chances are, if you're not a pro, you're doing your work in your regular user environment. This probably includes chat programs, info tickers, and most likely a whole slew of little widgets sitting down in the system tray, just waiting to kick off some specialized program. Most of these things steal a little memory and a little CPU, and some will leave behind a task or process even after you've shut the main program down!

If you're on an operating system that lets you create multiple user environments, create a new user called something like "RENDER." Keep the environment as simple as possible with only the bare minimum of programs starting automatically.

Make sure your render happens completely within memory

Sometimes you can solve your problem if you just hit it with a bigger stick... of memory that is. If you've got the money, and your system can take it, by all means go for it. If you've already maxed out your current memory, chances are you'll do the same on future projects. However, adding an new memory stick or two at the very last second is rarely a realistic option in a crunch.

If your OS HAS performance meters:
Make sure the CPU stays at 100% for the full duration of the actual render. It will dip during the object load, and again when writing the resulting image. If it doesn't stay at 100% in between, chances are you've hit your RAM limits. (Advanced OS's let you monitor page space directly.)

If you DON'T have performance meters:
To determine if your memory is slowing you down, kick off a render and watch both the messages in the render panel, and your harddrive light. Once the objects and texture images are loaded the harddrive light shouldn't light again until the final image is saved to disk. If it comes on for any more than a very quick blink during the render, chances are you've hit your RAM limits.

Change your screen resolution

If you're running short on RAM and your system uses on-board graphics, consider going to a lower screen resolution for the term of the render. This may buy you a few megs of RAM.

Choose your features carefully

If they're not absolutely necessary, make sure that both radiosity and caustics are turned OFF. Features like this can easily multiply the time required when used. Especially when used incorrectly! If you fiddle with a scene enough (say messing with lens flares) it's even possible to turn radiosity on without realizing it.

Turn off lights that won't effect the current shot

Lighting is very costly when it comes to rendering. Keep the number participating in any given frame to a minimum. For example: say your camera is moving within a house, it's left a room and the lights from that room will no longer have ANY influence on the shot. Fade those lights to exactly 0% intensity. Any light that is NOT at exactly 0% is still participating in the calculations!

This can get very tricky when ray tracing because objects often reflect conditions BEHIND the camera. You may need to consider a slow fade in light levels.

LENS FLARES do not actually require that their parent light participate in lighting the scene. If you're just looking for the flare effect, and don't really need a point light there, set its intensity for 0%.

Choose your shadows carefully

For most scenes, mapped shadows will render faster, and look nicer than ray-traced ones. Experiment early in your scene building to see which will give you the best bang.

See through stuff ( both transparent AND dissolved )

Transparency can be extremely costly depending on how much of the frame it consumes. Partially dissolving an object is the same as making it partially transparent, so watch out for both conditions. Rendering a top down view of the contents of a ranch house with a roof that is 95% dissolved will take something like 10 times longer to render than the house with no roof at all. If you don't need to see an object, make sure it's exactly 100% dissolved. If it's 99.9% dissolved, it's still there putting huge demands on the render.

Choose your Anti-Aliasing wisely

More Anti-Aliasing passes won't necessarily make your output look better.... especially on video. Use the "Limited Region" option on the camera panel to test render the portion of your image that has the highest (and busiest) contrast along diagonal lines. Unless you need high texture detail, you can probably get away with adaptive sampling on the AA.

Keep your polygon count down

This may seem pretty obvious to most animators, but if you're like me, you like to model in the details. If the render you're crunching is not a final render, consider swapping in a lo-res model with much of the detail left out. Sometimes your object will travel so far away from the camera the details won't be seen. If so, use a pair of objects... a lo-res for distant shots, and a hi-res for close ups. Lightwave will eliminate objects set to 100% dissolve before beginning the render. Which ever one you're not using will not add to the calculations.