Rendering Options

Most of the rendering options of Sasquatch are found in the pixel panel, including image quality, RAM use, alpha channels, and rendering features like transparency. The panel also controls global wind and shadowing options

Antialiasing (AA)

The most important quality setting for Sasquatch is Antialiasing. Fur and hair make very thin fibers, and small details like these (usually much narrower than a pixel) are very likely to cause image artifacts. Sasquatch can reduce these artifacts by using more RAM rendering time.

LightWave has its own antialiasing scheme, and Sasquatch works with it seamlessly. There are several Sasquatch options to customize and optimize the antialiasing to improve quality and speed.

The most important (and most used) control is Antialiasing Level, ranging from 1 to 4. Higher values will produce higher quality images at the expense of more rendering time. It's usually best to keep this number low (1 or 2) when you're making test renders, but increase it (to 3 or 4) for your final, highest-quality, render.

More antialiasing will usually increase your rendering times, but more importantly Sasquatch will need more RAM to store the rendered data. You can specify the maximum amount of RAM to use with the Layout RAM cache (MB). This defaults to 96 MB, but you can increase it if you have a lot of RAM in your machine. (Or decrease it if you don't have much RAM, perhaps on a laptop.)

If Sasquatch needs more RAM than you specify, it will switch its rendering mode to render multiple, smaller, segments which need less RAM. There is no change to the rendering quality, but the total rendering time will usually increase. Therefore you can usually increase rendering speed by using more RAM, with no change in quality.

Sasquatch prints how many segments it's using to the right of the cache control. This is useful since you might find that changing the cache RAM size just a little bit will lower the segments from 2 to 1 which may increase rendering speed a lot. (Don't worry about precisely setting this value to minimize RAM, though, Sasquatch will only allocate as much as it really needs.)

LightWave Antialiasing

LightWave's antialiasing is independent of Sasquatch's. You can use high antialiasing for LightWave's geometry, but a different setting for Sasquatch's. This is very handy since often Sasquatch is the slowest rendering step, and you may want to use a high AA setting for LightWave geometry but a lower setting for Sasquatch.

The most useful antialiasing option is called One-Pass Antialiasing which is on by default. This mode eliminates the need for Sasquatch to re-render the fur or hair during each of LightWave's antialiasing passes. This mode makes Sasquatch considerably faster, but it takes more memory and does not motion blur. One-pass rendering is only active when LightWave is using multiple-pass antialiasing. The memory that One-pass uses is printed by the activation button. This extra memory can become quite large for very high resolution images (a 2000 by 2000 image will use 80 MB), so it may be better to turn off One-Pass in these cases.

But sometimes you want to make Sasquatch render multiple times every frame if you want to use LightWave's motion blur or depth of field (DOF) effects. If you want Sasquatch to respond to motion blur or DOF, you should deactivate One-Pass Antialiasing to make Sasq

Freeze

Another feature of Sasquatch is the ability to freeze renders, where Sasquatch renders an image and remembers where the hair and fur is and what it looks like. The next time you render, Sasquatch does not render but simply composites the same hair effects into the new LightWave rendering.

This mode is useful when you're tweaking your LightWave scene. If you are adjusting an image map defining the color of a woman's face, it's annoying to have to wait for Sasquatch to render hair when the hair is unchanged. The Freeze mode of Sasquatch lets you tweak the normal LightWave surfaces and lighting and see the result quickly without waiting for Sasquatch to render every time.

To activate this mode, use the Freeze Fur Render button to tell Sasquatch to remember the next rendering. Render a frame, and Sasquatch will store the hair and fur effects. Any later renderings won't activate Sasquatch's renderer, but will just composite the previous hair onto the LightWave image.

To tell Sasquatch to discard the frozen image, use the Flush button and Sasquatch will compute and store the hair image the next time you render. Turning Freeze Fur Render off will discard any frozen image and make Sasquatch render every frame again as normal.

Freeze mode isn't magic, it's just a convenience. Since Sasquatch is just compositing an image onto LightWave's output, if you move objects or the camera, the hair will still be shown in the original location. Freeze is mostly used to quickly preview LightWave surfacing changes.

Transparency

Sasquatch's renderer can show hair and fur behind transparent surfaces such as a helmet visor or a car's windshield. This slows rendering, since Sasquatch has to compute transparency at every pixel, so this ability is disabled by default. If you need hair and fur to appear behind transparent surfaces, raise the Max Transparency Layers value. Only 1 layer is needed for most cases like a windshield, but you would choose 2 to see hair through two layers of glass, and so on. Sasquatch hair does not refract through glass. Your transparent surface must have an Index of Refraction of 1.0. Also, LightWave's Trace Refraction.

Alpha Channel and Z Buffer Selection

Sasquatch adds its effects to LightWave's alpha channel by default, so the output is ready for compositing. Sometimes it's useful to get an alpha channel of only the LightWave imagery, or only the fur, so you can choose what the alpha channel should output with the Alpha Channel option button.

Similarly, Sasquatch writes its Z depth information into LightWave's output, allowing LightWave tools such as Hypervoxels, volumetric lighting, and Digital Confusion to work properly. Like the Alpha channel, you can decide if LightWave's updated Z buffer should show just LightWave's effect, just Sasquatch's, or both combined.

Speed Optimazations

Sasquatch has several settings which usually speed up the rendering of fur significantly. They are slightly dangerous if the quality settings are too low, since rendering artifacts can occur.

Rearward polygon quality determines whether Sasquatch adds fur to polygons that face away from the camera. There's no need to render fur on the unseen side of a wolf! This usually gives speedups of about 30-40%. This speedup can be dangerous if you have long fur fibers; the fur from the rear polygons may droop or stick up enough to be seen around the edge of your object. If the quality setting isn't high enough, this fur will be missing. It's often hard to notice unless you see the fibers appear and disappear during an animation.

Sasquatch can also speed up by not rendering fur that's out of view of the camera. This can dramatically reduce render times, especially for landscapes which have a lot of grass that's not visible in the image. The out-of-view speedup also helps rendering when you have a lot of Sasquatch rendering segments.

Smaller values of Out of view fur quality make Sasquatch render more quickly but you run the risk of rendering artifacts. Like Rearward polygon quality, you can vary this quality to optimize your rendering times. If the setting is too low, you'll see missing fibers around the edges of the screen. You may also see fibers missing in horizontal stripes if Sasquatch is using multiple image segments.

If your rendering has artifacts or missing fibers, increase Out of view Fur Quality and Rearward polygon quality. This is by far the most common, and confusing, error you'll encounter using Sasquatch.

The best advice after you first set up basic geometry, is to try a 30% out-of-view setting, which can be a lot faster than the default of 90%. Compare the rendered image with and without the setting (this is easy using the QV image viewer) and look for any disappearing fibers. If you don't see any, keep the faster setting! Just remember that if you do start seeing missing fibers, you may have to set this value back higher. Animations are much more likely to show the artifacts.

Proper Out of view quality settings can double rendering speed when it's set correctly, so don't neglect it with complex renders! You can always guarantee perfect renders by using a quality setting of 100%.

For large landscape objects, often you care only about the fur (really grass) that's near the camera, and distant fibers just slow rendering. If you activate Max Distance Clipping, Sasquatch will render only the grass within a certain distance from the camera. If you obscure the horizon with a little fog (or other geometry) the image won't show the missing fibers in the distance. This option can speed up rendering dramatically (since Sasquatch can restrict itself to just nearby surfaces.)

Part of the speed improvement in Sasquatch 1.5 comes from new control over the shading algorithm used to make fur and hair. In some scenes, this can significantly slow rendering, so its quality is now adjustable with the Shading Quality control. This slowdown is especially noticeable when the ``Receive LightWave Shadows'' option is used, since LightWave's shadow queries are slow enough to dominate rendering time in many cases. By reducing the Shading Quality, fewer shadow calls need to be made, and significant speedups are possible. If the value is too low, however, the quality of the final render will decrease. In particular, shadows will start becoming blurry and less accurate, and specular highlights may become softer and dimmer. The lower quality shading is more noticeable during animations. You can always increase shading quality to avoid any problems. Increasing the Fiber Divisions setting also enhances shading quality.

In some animations, it can be useful to deactivate Sasquatch for only certain ranges of frames, either for testing or for a manual speedup. For example, if your Sasquatched character is out of view of the camera for part of a shot, Sasquatch's effects may not be needed for those frames and you can manually tell Sasquatch not to bother doing any work during that time. To use this limited frame range, just enter in the start and end frames in the Lowest Applied Frame and Highest Applied Frame controls. Sasquatch is pretty smart about optimizing out-of-view rendering anyway, but this option eliminates all processing completely.

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