Hair dynamics collision issues


Been having a problem with hair dynamics in 2.76b. I’ve set collisions and dynamics to what I thought would work, but it hasn’t. Once the particles reach the body mesh they start passing through it. Here’s the summary of my setup:

Hair object and body model are separate.
Hair dynamics settings for hair object:
Mass = 0.3
stiffness: 0.2
Random: 0
Damping: 0.5
Air Drag: 1
Internal friction: 0
Density Target: 0
Strength: 0
Voxel Grid Cell Size:0.1
Pinning goal strength:0

body collision settings (only changed soft body and cloth settings):
Outer: 0.2
Inner: 0.02

I’ve attached a video showing what’s happening(had to zip it to upload).

I can provide more info if needed, thanks! (6.25 MB)

set your emmitor for cloth in the physics tab and your head for collision. make a vertex group for the emitter and pin it in the cloth settings.

It made the simulation smoother but did not stop the particles from penetrating the mesh, even with the quality set higher.

try setting outer thickness for your collision object to a higher value. theoretically it should work, but I have encountered these issues as well.

increased the outer thickness value and apart from taking 5x longer to bake it didn’t do anything different. Looks like I’m going to have to fake the effect using weight paints.

I am not expert in blender. I tried lot of tests last 3 days. and did not find way to prevent particles from slowly penetrating mesh in Blender 2.76b.
here what i found out:

  • patricides will slowly go through mesh (if angle is sharp degrees and given enough time)
  • particles will NOT go through mesh if angle is low(they hit mesh almost horizontally) and will stay there indefinitely
  • emitter itself i could not make “collision friendly”, his child particle always passes through it
  • if you have plane you cant put collision, but when you “solidify” it then collision works better

That’s pretty much what I learned too. I found a decent solution using a mixture of weights and physics. I’ll post a video of the fix in a few days.

Side question: is there any updated documentation to the new hair dynamics? I haven’t found anything short of buying a blender cloud subscription to see how they did it in gooseberry.

I remember when hair dynamics first came to blender, and there was a demo video…even back then everything appeared to work flawlessly in the video. so it’s doable, but remains mysterious.

So I’ve tried to recreate what I saw in the video here:
but the hair itself won’t collide. Attaching a video and a screenshot of the settings for both hair systems. Any ideas? (1.27 MB)

I just noticed this at

I saw that too, however its for 2.62, I’m using 2.76 and the settings no longer apply the same to my understanding.

That makes sense. Thank you for that info, I’ll have to listen to those podcasts. In the mean time I’ll play around with the old versions. Thanks again!

Hi All,

As this thread’s still under a year old, I figured I’d post a reply here before starting a new topic.

I’m wondering what the current verdict is with Hair Collision in Blender 2.78a ?

I’m having a really hard time getting a female human’s long hair to not penetrate her shoulders (and face and neck to some extent as well). Presently I’m using “deflector meshes” in hopes of getting the physics/collision to work, but nothing seems to help. I’ve tried collisions, various force fields as a work-around, all to no avail.

Any hope? Any work-around for this?

Here’s a video showing the effect. The blue and purple you see are the deflector meshes:

Here are screeshots of the settings for hair and the deflector. If anyone needs to see additional settings, please ask. I’d love to find a way to get this working!

I have exactly the same problems here, it seems like the issiue still isn’t fixed.
The colission box works at first for some hair, but after a few frames of animation it
completely passes through the collision box, even when the outer value is set to 1(highest).
It’s really frustrating, now i have to fake the collision with force fields and the whole process is a pain.
Even this method can’t stop the hair from passing through the head sometimes and kills my animation :mad:.

I don’t wanna hate but i am very frustrated and have to say this:
Sometimes Blender still feels really unprofessional, especially when it offers features which
seem great at first glance, but soon you find out that the feature is unfinished or bugged…

If there is any good working workaround or any new feature that fixes this problem and i
simply missed it please comment!