Hi, I am learning how to use Fibermesh for my project, and I’m getting strange results in rendering, as shown in the image below.
I don’t know what’s causing these artifacts along the edges.
Any help would be appreciated.
Hello @airun_71
There are a couple things that might be going on, but I can’t tell which from the picture.
- It’s important to understand that after being created, a Fibermesh subtool is in a special “live” state, that allows it to work with special brushes like the Groom Brushes. This is why a Groom Brush can style the strands as if they’re a fixed length that never changes, but normal geometry would be stretched until the individual polygons stretch out of shape. However, exporting and reimporting, or any operation that changes the topology will break this live state, meaning the strands just behave like any other geometry, and the strand polygons will then stretch and distort if you pull them out of position.
This might be whats going on in your mesh, as some of the strands are beginning to look a bit fat and chunky. You can tell if you select a large groom brush, and try to move the hair. If the strands stay the same length and stop being pulled at a certain point, then your subtool is still live. If the hair doesn’t stop being pulled and lets you pull it wildly out of shape, then your subtool is no longer live because of something that you did along the way. There is no way that I’m aware of to restore it to the live state, which is why fibermesh requires mindful handling.
- It also looks as if some of the strands on the bottom near the forehead have a different material painted on them. This could be the result of using a brush on them with either the “M” (material) or MRGB (Material + Color) channels active, which would cause you to paint the active material on the strands at the same time as you’re grooming them.
This part at least can be fixed by filling the subtool with the desired color and material. With the Fibermesh subtool active, select the material and color you want to assign, then use Color> Fill Object with the proper channels selected (M, RGB, or MRGB).
Hello Spyndel
Thanks for your reply. I checked the strands and you were right, some of them appear to be stretched.
I’m not sure when or how that happened. I’ve been using the Move tool to manipulate the shape, setting the Preserve Length parameter to 100, as many tutorials suggest. Usually, it works fine, but something must have gone wrong in the process. I also use some of the Grooming tools, but I prefer to use Move to have more precise control. Now I’m not sure anymore if that works well.
In order to use the Move brush (or most non-groom brushes) with a live fibermesh subtool, you will have to first go to Brush > Fibermesh > and set Preserve Length to 100. This will preserve the length of the strands, although the Move brush is a blunt instrument, not well suited to subtle grooming. Some deformation of the strands will be unavoidable with that brush, and you will have to smooth frequently.
I cant speak to what tutorials you’re watching, or for what version of Zbrush they were produced, but in the current program the Move brush with Preserve Length set to 100 is an inferior version of the basic Groom brush in my opinion. Your mileage may vary.
I see.
Someone also suggested to use Smooth tool to shorten the length. Guess that messes up the geometry as well?
Is there any other way to shorten the length without compromising the strands integrity?
Frequent smoothing is part of styling. It may help to use a Smooth brush with a lower intensity to keep from making overly drastic changes. If you hold down Shift while adjusting the intensity, it adjusts it for the active smoothing brush.
There are quite a few Groom brushes in the default brush menu, and more in Lightbox. Give them a try to see what they do.
Thanks Spydndel.
I realized that the Smooth tool is the reason for stretching the strands.
I’ll try to find another way to shorten them.
Also, another thing to notice, when the strands cross each other too much they create those artifacts in rendering.
I started the hair all over again, using exclusively Grooming tools, and I still get the same artifacts on the fringe edges in rendering.
Does anybody know what’s wrong??
I believe this is an issue that several people encountered.
Any help would be appreciated. Thanks
After experimenting with different tools I’ve come to the conclusion that, when the strands cross each other too much, the geometry gets messed up in rendering.