Sasquatch FAQ

A lot of problems you'll encounter are simple mistakes or misunderstandings. Sasquatch is a very large, very complex system, and it will take weeks to become proficient with it. From experience, we know there are extremely common questions and problems that everyone has, and we try to list them here. No matter how experienced you are, you may want to run through this list if you have a problem. Even we use this list!{It's embarrassing to waste 30 minutes thinking there's a Sasquatch bug when the answer is in the FAQ. I wrote both the software and this FAQ, yet on more than one occasion I've been fooled!} It's a very very good idea to read this list completely even if you don't have any problems, because it will at least alert you to limitations, errors, and techniques you should know about. This is the most important chapter in the manual to study.

Frequently Asked Questions

#1. My rendering has missing fur or grass in it. It looks like a horizontal stripe, like in the image below! Or fibers are missing from the edges of the image. What's wrong?

Horizontal artifacts from too low Out-of-view quality

Answer. This is a very common problem! Raise your Out of view Polygon Quality. A value of 100\% will completely prevent the problem, but renders may be slower. Too low of a setting can also cause shadow errors. More info

#2. Fur is missing from part of my object, like in the right side of the image below. It sometimes reappears if I move the camera or object. Or sometimes parts of my shadows ``pop'' into or out of existence!

Missing fur from too low Rearward polygon quality

Answer. This is the most common ``weird'' problem you might find, especially when you have long fur on a small object. To speed rendering, Sasquatch isn't rendering the fur that's on the backside of your object. However, the fur is so long, you can see those fibers even from the front! You can solve this by increasing Rearward Polygon Quality. . Too low of a setting can also cause shadow errors, especially at the "terminator line" between lit and unlit areas of fur. More info

#3. I'm using weight maps or UV maps, and Sasquatch is doing the wrong thing!

Answer. Weight and UV maps usually work with no problems, but there's one potential severe confusion if you define only a partial weight or UV map in Modeler. It's interesting that Modeler allows you to assign only some points a map value if you wish, leaving the other points undefined. This has some uses in LightWave, such as defining a UV image map to apply to only parts of your object but not others, but it can create some very confusing situations as well. In particular, when a weight or UV map is undefined for a region, we've decided Sasquatch will treat that value as 0, or ``Base'' as we label it in the ``S'' panel. A color UV or RGB vertex map (for texturing fur) treats undefined areas as ``white,'' so the natural colors you select for ``Salt'' and ``Pepper'' will be shown untinted. However, it is almost always confusing when you have unmapped points in your object; even LightWave itself displays and treats them a little mysteriously. Our strong, strong recommendation is to always define values for all of your object, leaving no points as "undefined." This prevents you from this potential source of confusion which can strike subtly. This behavior is not a bug, it's just a case where you're asking Sasquatch to apply a value that you haven't told it. If you get mysterious effects when using weight or UV maps, check to make sure that all of your points are mapped; it's a likely cause of your mystery.

#4. I'm making long hair on a guide. On the inside corner of a bend, the hair fibers twist and even loop in a circle. Help!

Answer. Your guide is forcing the hair to bend in a tight angle, but the lock Width and Thickness are too high to bend that tightly without the inner side "collapsing." This happens in real life too; you can tie a piece of string into a much tighter and smaller knot than a rope! You can fix it by reducing the Lock Width and Thickness, increasing Spline Smoothness , or changing your guide to have a softer bend.

#5. I'm using an image sequence on an S~panel, but it doesn't work when I re-load the scene.

Answer. Sasquatch doesn't officially support image sequences, since LightWave doesn't give plugins quite enough information to re-load them reliably. There are a couple of easy workarounds.

  • Add a polygon to your scene and make it unseen by camera. Then apply the sequence to the polygon in some channel and save the scene.
  • Apply the sequence to an unused channel in one of your scene object's surfaces.... a refraction map is usually a good candidate. Then save the object.

If you do either of the above steps, the next time you load LW, it should correctly identify the clip as a image sequence.

#6. The Sasquatch preview doesn't match my real rendering!

Answer. The Preview only shows changes in color and shading, not geometry changes like length or density. The preview also does not give exact results for specularity when more than one light is used (its approximation is very close though, just not perfect.) Finally, changes in Direct Lighting are not shown.

#7. Sasquatch doesn't show a spotlight's projection image.

Answer. Turn on Sasquatch's Receive LightWave Shadows option.

#8. I made an animation and the fibers or hair are moving when they shouldn't.

Answer. You probably have Wind or Flop active. More info. Droop will also make fibers bend if your object rotates. If you want to have drooping fibers that don't move, use Bias Combing instead.

#9. I'm using dynamics or wind, and the fibers aren't swaying enough.}

Answer. Obviously, you can increase the Flop or Wind values. But increasing Fiber Divisions can help too, which is not as obvious.

#10. Some of the demonstration scenes are broken. For example, I see no beard in the beard.lws scene, and the zebra_fur.lws scene is all white.

Answer. Many of the demonstration scenes load image maps to control color or density. These maps are in JPG format, and you haven't installed LightWave's JPG loader. Or you may just have your content directory mis-set. You want to set LightWave's content directory to the WorleyDemos directory.

#11. I composited fur in another program using the alpha channel, but it looks terrible!

Answer. Make sure to use LightWave's "Fader Alpha" mode. Fur and hair tends to make very fine fibers, which require careful compositing. Fader Alpha should be used for all LightWave compositing, and fibers happen to clearly show this because of their small size.

#12. I am using Droop, but some fibers are still sticking straight up.

Answer. This is correct, it's like real life. Vertical fibers resist gravity more than sideways ones.

#13. I am missing fibers on the inside of curved surfaces when I use combing. I can sort of see the outline of the object's polygons in the fur.

Answer. Sasquatch fur ignores object collisions, so it's penetrating right into your object. Try decreasing the length of your fibers, or decreasing combing strength or Maximum Sleekness. You can also subdivide and smooth your object in Modeler in some cases. Here's a short video that explains the problem and solutions

#14. I don't see fur behind a transparent object.

Answer. You have to explicitly activate transparency in the pixel panel, as discussed here. Also, make sure to turn on LightWave's Trace Refraction option and set your object's Index of Refraction to 1.0.

#15. I am making my object grow over time, but the fibers aren't growing with it! And they look sparser.

Answer.This is a feature! The number of hairs won't increase, and the hairs that are there won't stretch. If you want them to, you can explicitly animate them with the ``A'' buttons next to Length and Density.

#16. My landscape is taking a very long time to render.

Answer. It's not hard to make a giant landscape with literally a billion fibers on it. Sasquatch is very smart and won't render offscreen grass, but that may still leave 100 million fibers! Try to restrict grass to the foreground, and don't add Sasquatch to very distant areas like hills on the horizon. A tiny amount of fog can help hide the distant ground. Sasquatch can render landscapes very quickly, but you have to be careful not to be completely wild!

#17. Fur is appearing incorrectly on my concave polygons.

Answer. This is a minor Sasquatch limitation. You can simply Triple the polygon in Modeler to fix the problem for now. Note, a concave polygon has one or more sides which bend inwards towards the center. This is different than a nonplanar polygon. Triangles are never concave.

#18. My texture maps aren't appearing correctly, I don't see the sharp shapes I painted or textured. The preview does work, though

Answer. Increase Surface Subdivision, as described on here.

#19. My shadows flicker slightly during animations.

Answer. Increase your Shadow Map Resolution and Shadow Quality settings. Increasing Shadow Softness can help a little bit too. If the shadows show strong artifacts, it's probably LightWave multithreading or using another shader on the surface when you shouldn't. Finally, increase Out of View Polygon Quality and Rearward Polygon Quality, since they affect shadows too.

#20. I'm trying to extend fur from a surface with Creep, and it isn't working smoothly.

Answer. Creep works better when your underlying geometry has more polygons. Subdivide the polygons in Modeler and the Creep effect will work better.

#21. When I zoom close to very thick, bent fibers, I see little notches cut out of the hairs.

Answer. This is normal. Sasquatch assumes that your fibers are so small you'll never see these notches. It's a tradeoff to accelerate the rendering speed. It's very rare to see them unless you're very close or have very coarse fibers.

#22. My wind effects aren't very smooth.

Answer. Use higher Surface Subdivision. Also, Gust Patch Size can change the "feel" of wind a lot, so experiment with different sizes.

#23. My guide renders long hair as a giant tangled mess.

Answer. Your Clump Size, Lock Width, or Lock Thickness is too big.

#24. My hair has many more colors than I've selected in the Salt and Pepper settings.

Answer. You're seeing the effect of the Hue Vary control, described here.

#25. I've increased my Clump Haircount and now Sasquatch renders no hair at all.

Answer. As Clump Haircount gets larger, you get fewer clumps on the surface, but each clump has more fibers. If you increase the value, you may make the clumps so sparse that none will even appear on your surface. Decrease Clump Haircount and they will begin to reappear.

#26. When I generate a Preview, the render I see in QV or Image Viewer looks awful.

Answer. It's normal, you're not expected to make "final" renders with Preview turned on. The quality is low to speed up the rendering.

#27. My fibers float off of my surface, or poke through the back side!

Answer. Your Clump Size is too large.

#28. Hypervoxels does not work, or has artifacts!

Answer. Some LightWave tools such as Digital Confusion and Hypervoxels depend on LightWave's Z buffer to produce their result. A bug was fixed in LightWave 7, finally allowing Sasquatch to write to this buffer, enabling the use of these tools with Sasquatch's effects. This is especially useful for volumetric lighting and Hypervoxels. Since LightWave does not antialias the Z buffers, you will get better results if you turn off Sasquatch's "One Pass Antialiasing" feature and turn on LightWave's antialiasing. This forces LightWave to use multiple passes to give smoother results.

#29. My render seems to show some fur from the back side of my object! It looks like my object is transparent!

Answer. This artifact happens rarely, only if you have the "One Pass Antialiasing" speedup option active, as well as a sparse layer of fur. What's happening is that Sasquatch is remembering part of the color of the more distant fur since it may need it on a differerent rendering pass. This color can show through later even if there's LightWave geometry in the way. You can always avoid the problem by turning off "One Pass Antialiasing."

#30. I'm trying to make velvet. Sasquatch is really slow!

Answer. Velvet is made of so many fibers, it's really a surface, unlike fur and grass. It's not practical to try and render every strand on a large velvet patch with Sasquatch.

#31. Sasquatch doesn't respect Radiosity settings in LW 9.5.

Answer. In LW 9.5 you need to turn on the "Volumetric Radiosity" option in the LW Global Illumination panel in order for Sasquatch to respond to Radiosity settings.

#32. Whenever I lick a flag pole in the winter, why does my tongue stick to it?

Answer. Due to global warming, this is no longer a problem.