Found 15 posts.
Search results Show results as topic list.
Work in Progress » Korean Visible Human (KVH)
- msawtell
- 21 posts
- Offline
Work in Progress » Korean Visible Human (KVH)
- msawtell
- 21 posts
- Offline
Work in Progress » MRI scan volumes from gif files
- msawtell
- 21 posts
- Offline
cool I recently presented a similar workflow at SIGGRAPH Asia the other week. I went a step further and we figured out how to export it into minecraft walking around inside a brain is trippy.
I need to update the materials… maybe do a youtube demo vid. time time.
http://www.minecraftforum.net/topic/573759-houdini-to-minecraft/page__gopid__7574978 [minecraftforum.net]
I need to update the materials… maybe do a youtube demo vid. time time.
http://www.minecraftforum.net/topic/573759-houdini-to-minecraft/page__gopid__7574978 [minecraftforum.net]
Houdini Lounge » cmiVFX Martin Sawtell Directable Particles & Point Cloud
- msawtell
- 21 posts
- Offline
Hi guys! Thanks for the support, these videos are meant to show my workflow for smushing particles around with vectors sampled from geometry via a pcopen. There's also a section on generating a particle source from PCwrite in mantra, but that's more of a tertiary thing.
Yeah they would probably be a bit crazy for someone completely new to Houdini, but I explain it in a very detailed way (3 hrs of talking woo). So it's still possible to get through it with minimal experience, but probably not easy.
-M
Yeah they would probably be a bit crazy for someone completely new to Houdini, but I explain it in a very detailed way (3 hrs of talking woo). So it's still possible to get through it with minimal experience, but probably not easy.
-M
Houdini Indie and Apprentice » [help] weird point normal in H12
- msawtell
- 21 posts
- Offline
Yeah I was getting the same thing, drove me nuts until I turned the h11 driver back on
Houdini Lounge » How to attach cloth object to motion path?
- msawtell
- 21 posts
- Offline
Hi there, a while ago I threw a cloth car at an object from a curve, you can have a look inside and see how I used the pintoanimation attribute to release it from the curve:
http://www.msawtell.com/research/carcrash_msawtell.hip [msawtell.com]
enjoy!
-Martin
http://www.msawtell.com/research/carcrash_msawtell.hip [msawtell.com]
enjoy!
-Martin
Technical Discussion » stack of paper - blown away
- msawtell
- 21 posts
- Offline
The best (well, one of) way to do it would be with cloth- just make a grid object, instance it around the place with a copy sop and make that whole /obj a cloth object via the shelf.
Then just put a fan force or wind in and off you go! Drag would be nice too, and of course gravity. Turn on self collisions too once you have the physics right. If you want to toss them at something, animate them and then set the pintoanimation attribute from 1 to 0 when you want to release them to the cloth sim.
Then just put a fan force or wind in and off you go! Drag would be nice too, and of course gravity. Turn on self collisions too once you have the physics right. If you want to toss them at something, animate them and then set the pintoanimation attribute from 1 to 0 when you want to release them to the cloth sim.
Technical Discussion » animated vines/seaweed/grass
- msawtell
- 21 posts
- Offline
I once did it with strips of cloth that were pinned to the ground. Reverse the gravity force so it is pointing ‘up’ and plug a sine curve into a wind DOP and you have wavey seaweed!
Houdini Lounge » Crumpling and Tearing in Houdini 10
- msawtell
- 21 posts
- Offline
^^^ Sure did, looking forward to having that as a reference too. Edit: Oops, wait I thought you meant the Toronto tech evening on Mantra. Not sure about the LA one sorry.
OK I had some people ask about having cloth advect fluids and vice versa, there is no solution built in to the cloth solver as yet that will handle this but I whipped up some solutions for you to try. Advecting a volume is easy enough, you generate an SDF off the bit of cloth and off you go, the other way around makes use of a new vector attribute called fexternal. It allows you to apply forces to the geo on a per point basis, so I used volume sample in VOPs to grab the velocity from a smoke sim and modify fexternal.
Pretty picture:
OK I had some people ask about having cloth advect fluids and vice versa, there is no solution built in to the cloth solver as yet that will handle this but I whipped up some solutions for you to try. Advecting a volume is easy enough, you generate an SDF off the bit of cloth and off you go, the other way around makes use of a new vector attribute called fexternal. It allows you to apply forces to the geo on a per point basis, so I used volume sample in VOPs to grab the velocity from a smoke sim and modify fexternal.
Pretty picture:
Houdini Lounge » Crumpling and Tearing in Houdini 10
- msawtell
- 21 posts
- Offline
Sure, here you go. It needs some tweaking as it was done when cloth used a different tear model (where it was allowed to tear off single polys).
However you can see the basic workflow, feel free to play around with it. Of note is the trick I used to set pintoanimation to stop the whole sheet from wobbling around (using an attribute transfer from a POPs system).
However you can see the basic workflow, feel free to play around with it. Of note is the trick I used to set pintoanimation to stop the whole sheet from wobbling around (using an attribute transfer from a POPs system).
Houdini Lounge » how to resampling a polygon object
- msawtell
- 21 posts
- Offline
You can actually use the subdivide SOP in this case too- tick the “override crease weight” box and set the crease weight to 1. This takes a poly and just turns it into 4 polys (in the case of a quad).
Houdini Lounge » CLOTH: some questions/one RFE
- msawtell
- 21 posts
- Offline
Cloth and RBDs do not pass forces back and forth between each other unfortunately. So what's happening is that the RBD sim is just ignoring the cloth that's there and having the ball keep falling, so the cloth eventually gets stretched so much that the solver freaks out. (I'm doing this on build 245 btw, it has changed a bit since then but that basic problem is the same).
One way to do this would be to make the sphere a very stiff cloth object, and drop that on there. If you didn't want to see the deformations that would technically result on the sphere you can make another sphere geo follow around that centroid.
It's good that you have the sphere as a polygonal one, as primitives or poly meshes won't work with cloth.
I'm not 100% clued up on the collision model, but I really doubt you can be that selective about how to calc collisions, mainly because the model needs to take into account some fairly crazy eventualities. IE a giant poly with a sphere of tiny ones hitting it, or an object that cuts a piece of cloth very fast with strange topology, etc. The cloth solver actually triangulates everything (I think) and then bases collision off that, with non planar polys that have N sides things get interesting.
Turning off bits and pieces of that algorithm would cause things to get very unstable I think. The Symmetrize max sides parm on the cloth solver is actually the input for that triangulation method, I'd need to refresh my memory on it before I offer any more advice there.
edit: as for the “cannot retrieve data from previous solve thing”, it will actually give you the error as a node message on the frame it dies, but since the next frame will look at THAT frame and go “oh no I can't retrieve stuff” it wipes the message. It can be hard to know what's going wrong unfortunately, it would definitely be good to get more feedback with it.
One way to do this would be to make the sphere a very stiff cloth object, and drop that on there. If you didn't want to see the deformations that would technically result on the sphere you can make another sphere geo follow around that centroid.
It's good that you have the sphere as a polygonal one, as primitives or poly meshes won't work with cloth.
I'm not 100% clued up on the collision model, but I really doubt you can be that selective about how to calc collisions, mainly because the model needs to take into account some fairly crazy eventualities. IE a giant poly with a sphere of tiny ones hitting it, or an object that cuts a piece of cloth very fast with strange topology, etc. The cloth solver actually triangulates everything (I think) and then bases collision off that, with non planar polys that have N sides things get interesting.
Turning off bits and pieces of that algorithm would cause things to get very unstable I think. The Symmetrize max sides parm on the cloth solver is actually the input for that triangulation method, I'd need to refresh my memory on it before I offer any more advice there.
edit: as for the “cannot retrieve data from previous solve thing”, it will actually give you the error as a node message on the frame it dies, but since the next frame will look at THAT frame and go “oh no I can't retrieve stuff” it wipes the message. It can be hard to know what's going wrong unfortunately, it would definitely be good to get more feedback with it.
Houdini Lounge » H10 Promos and session files
- msawtell
- 21 posts
- Offline
Yeah for sure, though a lot of this stuff is reading all sorts of crazy cached sequences. What I'll do is make a simpler version of the car stuff so the workflow is demonstrated and the world scale + physical properties are the same. I'll see what else I can get together too so that people have a reference for material settings in cloth (ie rubber, cloth, metal, tissue paper etc).
There will be a technical evening coming up on cloth, so we'll publish the recordings of that too.
There will be a technical evening coming up on cloth, so we'll publish the recordings of that too.
Houdini Lounge » H10 Promos and session files
- msawtell
- 21 posts
- Offline
Hi, I did the cloth ones- I'll look at bundling up some scenes and submitting them to the exchange. Let you know when they're up. If there are any questions about how I did them, ask away.
-Martin
-Martin
Technical Discussion » Force Quad Topology on Mesh/Iso Offset Surface
- msawtell
- 21 posts
- Offline
I've recently been mucking around with resampling meshes, a good way is to scatter points on the original mesh, then copy metaballs to it. You can also use a Particle Fluid Surface which gave me some clean results. The problem is then that you have a “bag” that follows the original topology, it can be difficult to delete the side you don't want.
-
- Quick Links