I’m working on (well trying too) an idea for an overall Eyelash workflow and a possible solution using Geometry Nodes.
Now I pretty much have the overall workflow in my head, which if it works could provide a somewhat flexible system for character Eyelashes. In general I think it will work, but I need to actually build and test it to make sure.
That currently introduces two problems.
I’m not totally sure the the Geometry Node component that I have in mind is actually doable.
I totally suck at Geometry Nodes, it just does my head in.
It’s a basic low subdivided plane, where I manually selected the edges that I pretty much want as guide lines and stored that in an attribute to use as the location/direction that I want the Eyelashes to be.
If there is maybe a better way to do that, then all good, HOWEVER, the basic shaped plane as being the base needs to remain. That has to be the template from which all the eyelashes ‘sit’, with one long edge being the root and the other being the tip. While all eyelashes follow the overall shape and curve direction of the plane.
Now there are a bunch of things that need to be done/adjusted, like a smoother curve of each eyelash (without just making the plane more subdivived) along with better control of the radius along the root to tip and all sorts of minor rotation/placement randomness, but before we even get to that, there’s the initial problem…
How to treat those initial curves as guilds and then interpolate a bunch more between them, while still pretty much ‘sticking’ to the base plane.
This looks and sounds somewhat like a previous go/attempt at using GN for Eyelashes and while it all looks good initially, it tends to break down in further testing.
Issues tend to be:
Can’t parent/weight paint a curve to an armature, this needs to hold up in full character animation, hence the plane.
Even if one finds a way around the first issue (which previous attempts did), the moment you start rotating/spinning the head/character around, there are tipping points where the position/rotation of the eyelashes just ‘freak out’. Basically it ends up broken and you won’t totally know where and when that will happen, until you watch the animation to see if the eyelashes snap back and forth or totally invert direction, etc. Again, hence the reason for the plane.
If for any reason during animation one needs to control the position/rotation of the tip of the eyelash, you basically can’t do it. Like for example closing the eye but stopping the ends of the eyelash cutting into the bottom eyelid. Again, with a plane it’s possible to rig/control both the base edge and the tip edge.
I tried playing around with it a bit more and got some sort of interpolation with the curves, but that created a whole bunch of other issues.
