houdini as a animation packg.

[djordje]

I am starting to learn houdini these days, and I am pretty animation-orientated .

Till now I worked in maya [ a lot], and a bit in XSI and max. Mainly all of my works, including rigging and animation is done in maya. From time to time [when there is not enough time for building a rig from scratch I do some things in combination with kaydara motionbuilder, which has amazing rig]... to cut the long story short: I read about animation tools on sidefx site, and heard some opinions from people on Jason Schleifer's forum Jonh and And His Dog, but I'm eager to hear more from people who do the serious animation& rigging work in houdini.

So, I supose most of you are familiar with rigging and anim. workflow in maya, XSI [at least one of them], and that you can write something to compare and describe them according to houdini.

thank you in advance

and much respect

[mark]

hi.. im not an advanced user so i wont comment.

but you should download the apprentice version, and try it - especially CHOPS (there are tutorial videos for that), i think that will impress you.

[djordje]

heheh

I downloaded it [version 7]

and I am learning it already.

and I 'am impressed already

[deecue]

i can't comment much either, but what you will be able to take advantage of in houdini in a big way are two things: its proceduralism and CHOPS.

proceduralism meaning... oh crap, i want to add a 6th finger to my character.. instead of redoing the whole rig like in another package, let me just add the appropriate bones, weights, and captures and get on with my life.

chops meaning... having complete control over how the rig will react and creating extremely complex motions.

but it def isn't something to jump into.. if you're new to houdini, it might be a little difficult getting used to the interface (which many of us have grown to love) and i see many people give up on it to soon. and chops is pretty intense at times IMHO... so don't give yourself a week and toss it aside if things don't seem to be going just right. the more advanced capabilities of houdini (including character) will not be produced by a few button clicks.

[Jason]

Hi Djordje,

I'd suggest you look at a few excellent and unique features of Houdini which help incredibly with animation only:

In setup:

*) The Pose operation : lets you pose Bones with extraordinary interactivity. Never seen anything like this elsewhere.

*) Handles - Persistent Handles. Houdini has many great handles/manipulators to choose from, all of which can be bound fairly easily by the user, especially when creating custom nodes.

*) HUD Sliders : Sliders on the viewport for things like facial controls.

In KeyFraming:

*) Handles can be keyed by hotkey, etc

*) The best Channel Editor (Curve Editor) around, IMHO.

*) Full Dopesheet

*) Animation Spreadsheet

*) Featured playbar -improving every week before the 7.0 release.

*) Playbar middle-click-drag HOLD animation to duplicate poses.

*) Expressions in any field for cycles, etc.

In curve manipulation/processing:

*) CHOPs - shift/slide/warp/load/save/composite/blend/smooth/whatever groups of animation channels. Not enough can be said about the power of CHOPs and animation processing.

*) Motion capture data can be processed by CHOPs effectively.

I stuck to the animation tools because you could write several pages on the rigging, skinning, binding, blah blah blah in Houdini.

Hope this helps you out a little...

Check out the example characters can come with Houdini (look in the help for the little girl character).

Jason

[sibarrick]

Hi Djordje,

I think you will find that the overriding mantra ( forgive the pun ) with houdini is that it may take longer to set up basic stuff but in the end you reap the rewards. You can usually push things much further in Houdini whilst still maintaining great flexibility. However if you aren't planning on reusing anything or you only have a day to do something anjd you don't need "cutting" edge then you might find Houdini frustrating.

The great thing is though that it is so easy to experiment, once you know your way around that is.

Also in terms of character tools they have been greatly improved recently and are changing and getting better on an almost daily basis.

I would add to Jason's list

1. Takes - haven't seen this anywhere else, still very new and need experimenting with.

2. OTL's - can't believe he left it off, I'm sure he had a good reason

It's one of the more advanced features but once you get into them you'll love 'em. They allow you (if you are careful ) to start animating a character before it is even finished and keep updating it right up to final render without having to break a sweat.

3. Animation blocking in mplay. - Totally new and still a bit buggy, but this looks like a great feature, again I haven't seen this before, but my experience of other packages is a little rusty.

That's my 2 penneth .

[djordje]

well,

Now I am more atracted to houdini then ever

The interface is a bit when you're used to maya, but when I rememember my first time sitting in front of maya , and that I was something like: what the f*is this.... now, think I could work in maya with my eyes closed... so everything can be learned...

Once I get into the basics of houdini, it'll be easier to work...

Anyway

Thanx for your thoughts people, now I am going to workworkwork and when I make something I'll post it for you to see.

[mark]

it took me 3 attempts to get into houdini, it just felt alien - i thought this will take 3 lifetimes to learn, so i hear you

actually its lucky xsi EXP is so pitifully supported on linux i might never have tried houdini

[deecue]

yea i was kinda lucky on this one.. houdini was my first serious 3d app that i got in to. i did some max stuff back in the day but not enough to compare and say 'why isn't it like this or that'..

so now the only problem is, i'm trying to get myself in to other progs just for the sake of learning and be open to multi-platform concepts and i get all pissed at how destructive everything is since houdini was my first.

[TheUsualAlex]

Yeah, Houdini is my first serious 3d apps, too. Although I started out with Softimage back in late 98 when I got a chance to play with it at an institute. Then when Siggraph 99 came, I happened to passed by SideFX both and decided to find out about student licensing of Houdini (I was saving up money for Softimage student license at the time). For some reason, at the time, I didn't get a good impression with a few Soft reps at Siggraph. One of SideFX representive was pretty friendly and so I got a chance to talk to the edu manager at SideFX (Hi Ray!) and have quite an email correspondence. So that pretty much got me off the ground and give SideFX a try. Lo and behold, I really loved Houdini even from the first use. I really love the flexibility that it offers. I didn't even know that much about 3D at the time. Houdini 7.0 has come a looooong way since version 3.1, ya know. I know the veteran users can tell you even more of their war stories.

I find it fairly easy to learn other packages after I became comfortable with Houdini, actually. Now, whether the seasoned Houdini users really want to jump to another package is another question.

Also, one other things that I consistently noticed about Houdini is that it seems to integrate into a production pipeline really well just as it is.

Did I also mention that the SideFX folks are awesome? (Hey, I have never been employed by SideFX, so, I didn't get paid to say that. )

Cheers,

Alex

[MatrixNAN]

Hey,

3DS was my first then Maya which pissed me off so much on the rigging that I went to Houdini. lol That is a true story. Maya 4.5 dear god the rig inverted through itself everytime you opened the file. I thought I was taking crazy pills. Oh here is my unfinished rig in houdini but its more advanced than the tutorials. I will be looking for a job come the end of december.

Cheers,

Nate Nesler

Complex Foot Rig

[MatrixNAN]

Hey,

Oh yeah you might want to know this. The houdini character toolz are not all there yet. Thats not to say they don't have more than other animation packages for characters because they do in alot of areas, but when I was at the last houdini conference at Siggraph last year they showed off auto body builder's for the arm and were later going to have other parts of the body too. The auto tool created the arm fully rigged with realistically accurate muscle deformation and a fat slider bar that you can slide back an forth to add fat deposits into the characters arm. I suspect they are much further along on the project now then they were back then. In the meantime they have a muscle jiggle fake chop in 7. I can't wait to see what they pull out of their hat this year.

Cheers,

Nate Nesler

[edward]

Hey MatrixNAN,

Just curious as to what your thoughts on what's left in terms of character tools in Houdini.

[MatrixNAN]

Hey Edward,

Well I would like to see an influence objects like the metaballs but with NURBS and Polys. I have good reasons for this. The main reason is that Sidefx can never possibly cover every type of muscle rig that a studio might need. For instance a dog, cat, or unrealistic characters combining multiple creature muscle systems for that matter. Also Dynamics for surfaces would be great although you can kind of do this now with particles in the SOPs. Houdini is so wonderfully procedural that it will not be difficult to roll rigs into an auto rigger. Using some HScripting a studio can opwire guides that control the length and size of bones, control icons, weight maps, etc and then opunwire them and wire back the full control systems with all of these wire commands linked to buttons that can be run as a custom op. It would be even easier if SideFX had a switch op at the OBJ level because that would be so useful for rigging. You would then not have to write out any scripting for rewiring not to mention it opens other doors that would make for very useful tool sets like being able to switch back and forth from a hand entered interface and icon control systems or change the way the entire rig funtions by just a click of a button that changes the switch value. All of this could be done with no coding if there was an OBJ switch OP. I will be looking for you at the Houdini Meeting if you are going to be there. You have helped me so much over the last year or more and I would like to put a face with the name. Oh and a side note too, on the infulence objects I would want the ability to lock with geometry around it like maya does but also have the option of not locking to this geometry and being able to slide freely. The main reason for this is that if you wanted to do a cartoon character sliding down a hose in maya and you try to use influence object animated character can't because it will fuse to where ever you put the influence object in the hose at the time of setting up an influence object relationship. It could of course be used in other ways too. So if houdini had both settings that would be very cool and powerful indeed. I guess for the icing on the cake I would think back to Siggraph 2002 where there is a paper and a demonstration in the Siggraph Transactions DVD for the "Synthesis of Complex Dynamic Character Motion from Simple Animations. by C. Karen Liu, Zoran Popovic at University of Washington." It would be good if this biomechanic Dynamics system could be editable as a procedural asset so that it can be modified for other character types too. Not to mention how useful this would be to fast paced animation and crowd sims structure by creating a variety of animations based on simple modifications of on an animated sequence dicated by behavioral AI. That would be the other thing that would be kind of out there but I believe very useful, to have a system that could create a system of variables for a particle like a class and then have that accessible with a fast lookup system within houdini and also have this feature set for CHOPs, SOPs, VOPs, and maybe even OBJ. I mean graphically like the way the digital assets work because I know you can do this through scripting commands or HDK but that takes alot longer to setup and is generally messier than the graphical approach you guys have taken which I absolutely love. The reason for this is for crowd simulations where you can setup hit values, behavioral conditions, etc that can react off of others around them and allow for these values to be distributed from POPs to CHOPs, SOPS, VOPs, and even OBJ to either drive animations directly or to enter another decision structure that allows for a further and more complex break down on another subunit. Since Houdini is so procedural this would make alot of since to push its power just that much more. Like I said this would be the icing on the cake.

Cheers,

Nate Nesler

[meshsmooth]

In my opinion what is left in regard to character animation tools

Quaternion rotation interpolation and I am not talking about pissweak linier interpolation. They can be edited with Euler coordinates for us humans, but the trends in quaternion curves are readable by humans, even if the numbers ant. No more gimble lock EVER!

CHOP VEX operators to be able to take in N channels at a time and evaluate them in one go then export the individual floats one by one. I have already done this to an extent with a CHOP VEX VOP that is a wrapper to import channels other than the one currently being processed. The current drawback is it evaluates the code once for every float coming in. So if you combined 2, (float 3) vectors with a VEX CHOP it would have to run the calculation 6 times each time spitting out one of the floats.

My proposed solution is to have a vex chop be able to operate on N floats at a time. Then export them one float at a time. to operate on an inputted numbers of floats that don

[thekenny]

Nate,

If you use a blendOp set to sequence you get a switch like performance.

Have you looked at OTLs?

What you describe can be achieved via clever callback scripts and well thought out tools made as an OTL. We have done a tonne of that work here for this production, standardized widgets which every animator understands what they are intended for built as OTLs. Some of them are 3d objects used to help control IK/NoK solutions on the rig, squashNstretch, translation, rotation etc. Some are built to change their appearance based on their current state/function, and to save on screen space. We thought HUDs would work, but have a 3d representation of the HUD features instead was better for everyone concerned. OTLs have a lot ot offer you should take a peak at what you can do. Really we use them for two things, an asset which can be updated based on the definition being used, or as a tool with a specific purpose. Sometimes the lines get a bit fuzzy but for the most part it is working very well.

Personally I believe influence objects are a bit over rated, and slow. I've seen very strong deformations be achieved from bones/cregions alone, and better ones with an inflate network. I've also worked on a show where the entire creature was built on the fly with a technique which allowed for a very believable tight muscle/skin solution. It really depends on what you are doing. If you have a volume of work to do, ie a feature, you have to use the best method for that solution. Often that will be different if you have a single creature to make for a film. I'm a firm believer that rigging in Houdini has to be done with a slight twist. It may take longer, but the possiblities should be explored.

Dynamics would be great to have, but really its strength would come from its speed. Unless you can iterate quickly to make changes the tool would be difficult to use in production conditions. I've always liked the idea that a simulation could be "baked" into channels, allowing things in post simulation to be animated in a traditional manner. That would give you the best of both worlds.

As for CHOPS, until you can properly interact with 'live' channels and redirect them back onto themselves and still be able key them on the object in question, I'll use them sparingly.

just my 0.02CDN

-k

[old school]

I'm a firm believer that rigging in Houdini has to be done with a slight twist. It may take longer, but the possiblities should be explored.

Slight twist yes. Please respect the twists and turns you have to navigate in other packages as well. I think that there are no more or less twists in Houdini once you pull out of the default rigging steps in any package. It is just that the other packages have had many more users pounding out various solutions with varying degrees of success.

The only step introduced by Houdini is the transition between Objects and SOPs. There are two new constraints in H7: rivet Object, sticky object that eliminate much of my rig expressions now and need to dive in to SOPs is reduced somewhat. Rivet is a point geomtry constraint and sticky is a uv geometry constraint. Nice stuff along with the blend Object.

Once you do advanced rigging, I bet all packages take about the same time. It is just that Houdini is very new to the character rigging game and it takes a bit of time to adapt to current state-of-the-art rigging techniques.

As for the influence objects, I played with these in Maya. They are easy to set up but limited somewhat by the shapes. I have seen influence objects coupled with extensive mel to create some muscle simulations but they are slow. Inflate is a comparable tool.

Attached is a quick prototype file showing a spherical object that is picked up by an inflate in the geo1 object done in H7. I even added some jiggle to the animated sphere blended in with a blend object. The inflate compared to the maya influence object behaves much better near the ends of the tube plus there is no "stepping" motion present that you get with infuence objects.

Also notice how the jiggle CHOP deforms the sphere in the space of the parent object. That is why I rotate the entire heirarchy to show that off. It is the little things that count.

I want to turn this in to a little tutorial so any comments are appreciated in a start to working up sophisticated muscle systems using inflate and anything else that helps out.

As for the chops issues, I agree with you Ken. CHOPs are great for working with the results from animated rigs. I limit CHOP integration in rigs to IK solvers and blending plus some dynamics utilizing jiggle, lag, etc.

-jeff

simple_inflate.hip.zip

[old school]

Oh, and about the vex limitation of outputting a single channel in CHOPs, it frustrates me as well.

-jeff

[thekenny]

Just to be clear, when i said you should look at it with a twist, I meant you should look at the end goal and rethink what you are doing. Just because you did a rig one way in another package and it used a specific tool doesn't necessary mean it was the only way to get the right solution. If you rethink what you are doing, you may realize that the rig can change, the geometry can be built a different way. It is the same trying to bring a total Houdini rig approach into another package. There are thing which have to be left behind in that translation.

-k

[old school]

Yes, I agree with that completely. Sorry for misunderstanding. I also think that leaving things behind means not missing out on equal or better functionality. I see it as leaving behind a specific tool and finding a different way of doing it in another package.

I found that the names of tools in Maya, XSI, Lightwave, Max, etc. were not consistent and evaluating rigs from different packages dificult until you actually dig and find out what is really happening. Houdini is completely different again with it's terminology and interface.