hair driven geo deformation setup

[KarlRichter]

I have used this setup on a number of projects and thought I would share. Basically, it is a simple setup that uses the wire deformer and hair system to animate geometry. I used to do this all the time back in Maya using Shave and a haircut, and was surprised that there isn't a more straightforward method to do this kind of effect in Houdini.

 

This is especially useful when you need to add flowers or other kinds of detailed grass to an existing grassy field that has wind blowing through it.

grass_example.hip

[Malak1000]

Hi, thanks for this. It looks perfect for my needs

I'm having a little trouble with your example file. The hairgen is complaining that its' using an incomplete asset definition...

 

EDIT: ignore me, I forgot about the ancient copy of Houdini we're forced to use at work. Works great on 17.5.

So as someone that's never used hair before, what are the advantages for this type of setup? I've seen a similar one where wires were just generated on the same scatter points as the instances.

Edited May 8, 2020 by Malak1000
Idiocy.

[KarlRichter]

The main advantage to this method is that you can use all the hair tools to setup and animate the wires to drive your deformations. Note that this does not work with instances, as each copy is actually being deformed, not just translated and scaled, by the wire.

 

[Malak1000]

Yeah I've dived into it quite a bit since my original reply and I'm really happy with it as a solution to large expanses of meadow grass. I'd not had reason to touch the hair/fur system before but I can see how powerful it is for this sort of thing. I'm planning on mixing your method above with un-instanced 'normal' hair as shaded grass to lighten to load a bit.

Thanks for the starting point!