View Full Version : Fiber FX Volume Render Woes

10-08-2017, 08:21 PM
Having a bit of trouble with Volume Render in Lightwave 2015.3
(Gee, imagine that! Trouble with FiberFX? Nah.... :devil:)

What I'm trying to do is simply get a reflection in the mirror. This was more of a personal experiment than anything else.

Turning off reflections and using pixel filter mode works just fine, except the reflection is bald. Turning on reflections but not using volume mode hangs my computer at 100% processor load. I shut lightwave down after 30 minutes, as temperatures on the CPU were climbing, and no progress being made. However, using volume mode (Stroke or Solid), with reflections turned on, leads to this. While the hair with guides turns out just fine, the body fur gets chopped up quite a bit. My render times are quite nice, a little over 3 minutes, and my fur coverage in pixel filter mode is excellent. But, I've a project that calls for reflections, and would like to work things out before heading into what passes for production here...

I've looked for options, and tried most of the ones I thought would work, to no avail. (Something I did to the reflection has the reflection all wonky, but I'll fix that later...)

Any suggestions?

10-11-2017, 03:58 PM
FiberFX reflections work fine for me in LW 2015.3 whether Volume Only is set or not, assuming I set the Reflections button on the Shading panel. LW 2015.3 is stated to have an "automatic switch" between Volume mode and Pixel mode for any FiberFX item that caught in reflections, etc.


10-12-2017, 10:11 AM
The reflection actually looked pretty decent, but the procedural fur on the character went all to heck, looking like someone took chunks out of it. That's the issue I've got, and that I'd like to solve. A few things - the model is in multiple layers, with the three sections of FiberFX - body, hair, and tail - in different layers. Does everything need to be in a single layer for it to work right? There's a very particular reason things are set up like that, and it has to do with FiberFX itself; With Sasquatch, I could have everything in one layer, because it was based on surface, not by object & surface, with everything sharing the object's settings...

*edit* And putting everything into a single layer didn't work (had 2 sets of guides and procedural fur - idea was to use instances of FFX for each); Trying to activate crashed FFX, taking layout with it. (LW 2015.3 x64, Win10 Pro).

10-13-2017, 03:29 AM
Just a few wild guesses that have not much to do with ffx: is there a chance that there might be double geometry that turns visible once reflections rays hit it? Did you try to raise the raytrace depth?

10-13-2017, 10:42 AM
I'll double check the geometry, to be sure, but I don't think so. I've raised the ray trace depth up to 100, in steps of 10, and there is no change.

*edit* No doubled geometry. merging points (m) only had one point merge, and no polygons under unify polygons (shift-i)

I'll try another model and see if I get similar results.

10-14-2017, 08:37 PM
Been running some experiments on a simply quadsphere, with a mirror object. I can get a nice, reflected, coat of fur on the ball. Looks really good, though the render times are a bit long. Which leads me back to the model in the original image. Something tells me I have a(nother) nonsensical limitation of the current FiberFX I'm up against.

The model in question is all quads and tris; there are no 2 pt. polygons in the procedural fur area. What I do have are several different surfaces, and the main fur generating surface is one of them...And that wasn't it (surface name other than Default - I still need to scream, though). I got the reflection corrected, but not the dicing effect on the fur. I think I know what is going on now...

*edit* And I think I've found the problem... Despite being 100% in volume render mode, FFX is picking up the pixel filter settings, and that, in turn, is somehow messing up the volume render.

*edit 2* It's related to fibers per cluster and cluster size 100% density and 1 fiber/cluster @ 3mm cluster size, and the problem goes away. Now, to try increasing the values...

10-15-2017, 05:34 PM
Still running experiments here on the character mesh; The rendering error is definitely tied to fibers per cluster and fiber radius. Either gets too large, and FFX begins having volume render errors, visible as "dicing" of the fur. The more the volumes overlap, the worse it gets.

What makes this annoying is the very different behaviours between pixel filter mode and volume render modes. Density, fibers/cluster and cluster radius behave very differently between modes, such that settings for one mode that look good will look terrible(or simply WRONG) in the other.

I hope this gets eliminated in FFX Next because this kind of stuff makes it very difficult to do any kind of work...

10-16-2017, 04:57 AM
Great of you to share your findings - as annoying as they might be... :-[
I take it *when* the new version gets out at last and it actually features fibers as geometry these issues should be a thing of the past - well, one can hope, right... :-\

10-16-2017, 10:24 AM
I figure Knowledge is Power, and the more people know about working with this plugin, the better, because it's like things about it are like some projects at work; We don't think you need to know that, so we're not going to tell you, but work on this anyway...

Usually, FiberFX, with multiple objects with fur, is about as crash prone as a demolition derby. I only had one crash during the evening, right at the very end, and I was able to save things out.

I'm hoping the next iteration of FFX solves some of these "Makes it really hard to work with issues..."

10-17-2017, 11:06 AM

Thought I'd share the nearly final results (I'm aware of the poke-through at the edges, it has already been taken care of).
2 layers of fur on the body (one short and tangled, the other long and straight). Quick bias combing courtesy of my Quick Comb script.

One thing I've noticed over the various iterations is that FiberFX does a very good job at the long hair with guides.

Definitely different settings than what I'd use in non-volume rendering mode, with somewhat different results. Still, I'm happy, the client's happy, so it's all good.

On to the next hurdle to overcome... And I'd like to find out where that shadow that's in the lower left hand corner is coming from...

10-22-2017, 08:10 PM
One thing you might want to look at is making the skin color in the muzzle and décolleté areas a bit lighter (under the lighter-colored fur). You'll still get the effect of seeing down to the skin, but it won't look quite as sharp/prominant as it does now. As it is, it almost looks like a coverage deficit or artifact.

Just a thought, good luck!

10-23-2017, 11:40 AM
Thanks for the tip. I'm still working on dialing settings in, but FFX's settings are very counter-intuitive. And there are definite issues with the volume render mode that are not easily or intuitively solved.

I'm hoping that FFX is easier to use in LW Next. I'm not holding my breath, though (and learning how to set up cameras to do the reflection...)

10-30-2017, 01:16 AM
I'm still working on dialing settings in, but FFX's settings are very counter-intuitive.

Calling that an "understatement" almost doesn't do it adequate justice. ;D

After this much development, there's just no legitimate excuse for it continuing to have as many workflow, styling, and even basic stability/determinism problems as it has. At some pt, LW3DG need to admit the feature just isn't meeting expectations/standards, and try to find a different, better solution.

I see LW Next (if/when it gets released) as FFX's "last chance" at redemption. If the Next version of FFX still has most of the same issues as current FFX, then IMO, they need to cut sunk costs and seek alternatives.

11-07-2017, 11:37 PM
ZENN Hair (from Dexter Studios in S. Korea) looks pretty good. Wonder if it could be licensed and adapted? Still, some fundamental changes to the public SDK would need to be made; this is a gripe from Mr. Worley re: the color picker not working in Sasquatch.

11-08-2017, 02:34 PM
A recent book cover I did using FFX was quite a pain. Ended up rendering it out separately then putting it together in Photoshop.

11-12-2017, 10:00 PM
One solution that has sprung to mind is to have actual guides - one for each polygon after subdivision - across the body. They can be grown and combed in modeler, and then fired over to Layout with the model. Length can be controlled -exactly-, which is always been a problem with FFX; Again, something that should be intuitive is not. Sasquatch, at least, gave you an estimate of how long the fibers would be, on average. Depending on how you specify length in FFX , it's all over the place (for 2 models, I can get either a max of 100mm (using a weight map) to some 3 meters (using the scale parameter)).

Dear God, I would NOT want to try to generate 48k spline curves to be converted over to 2pt poly chains, and then try to do anything with the model besides render in layout...
(Daz3D's Melody is my acid test... 64K polygons. I wish there was a reliable way to unsmooth a model).