Houdini's Character Tools

[TheUsualAlex]

I figured I might as well be the first one to start generating some noise over here.

Welp, it's almost 5.5 now. For those of you who have done character rigging in Houdini 5, what is your impression? How do you feel about Houdini's character tools thus far?

At the moment, I have mostly experimenting with Houdini's character tools to see what I can learn about it and how I can rig a character through what I know thus far. Most of the time, I am just trying to translate the rig methods I've been taught in Maya to Houdini. So far, Houdini is just as capable and I am very happy with the results.

Houdini's skeleton system is certain there and it's good in my opinion. Although setting them up can be a bit of getting used to because we are starting to move slightly away from the traditional set up technique and into the procedural approach. But, once done, they work like charm in my opinion.

Thus far, I have been able to try out the Paint Capture Weights. It was also much better than I have originally expected. The results are very predictable. To certain extent, I seem to find Houdini's CapturePaint to be faster than Maya's Smooth Bind/Paint Weight. I supposed it might have been an error in my workflow that may have caused this in Maya. But either way, I'd say Houdini's is very good now.

As for the "Set Driven Key Blendshape" method of deforming the joint area of the character, I think I have gotten it to work. Not sure what kind of problems I will run into when I start to rig my character. But, it can be done. And I am happy about this one since I find this method to be an essential.

So if you'd ask me, I will say that Houdini's character tools is very promising thus far IMHO. I am sure that Houdini 6 will be amazing. (Hopefully that will start to implement Cloth, Hair, and Fluid Dynamics so that we no longer need to resort to other packages to handle this. )

So. Anyone have any experience about this to share? Tips and tricks?

[betty]

Well i am fairly new to Houdini and am begining to learn the character tools.

At first glance they seem a little undercooked, but i have just begun using them so i look forward to pleasant suprises.

I was trying to use the follow curve kinematics and it seemed very primitive in its implementation, but again maybe i don't really understand it yet. I think it would be good if you can simply animate the curve and the bones would follow. Maybe if the goal of each bone would be constrained onto the cv or vertice of the curve and follow the curves movement, i think that would be cool.

The kinematics seem entrenched with CHOPS and this may be good, i don't know, but i would have thought that if the bones were treated like geometry one would have a greater deal of freedom with them. I have done character set ups in Mirai and it really is like a dream, i couldn't believe how easy it was and efficient with a remarkable workflow. I think a lot of this had to do with treating the bones as ordinary geometry and then being able to use the workflow of the modeling tools on the bones. An example would be the ability to mirror poses and mirror or reverse mirror animation from one side of a character onto the other.

It was also very easy to animate say a tail as you could grab all bones in one selection and then rotate them in one move. They would all rotate by the same amount which would give the impression of a tail moving. All of the bone animation was done in one move while in houdin it seems to me i have to choose all the bones and animate them individually. I hope this is the place where CHOPS swings into action and allows one to do things quicky and efficently, but i really have my doubts it will be so simple. But then again i imagine you will also be able to do a hell of a lot more in CHOPS once you have your setup( the beauty and power of Houdini ).

The other thing that could make things easier would be some decent tutorials. The character setup tutorial in the documents seems way to basic and they don't even show a simple animation like a walk cycle, the Houdini way. Now that would have been a great help. The documentation is something that has been mentioned so maby times and for a long time but it seems like SESI think it's fine or they are a little short on hands. They did just employ some guy from AW for who i believe had a hand in writing "Learning Maya"(i think that is what it is called) and some other AW documents, so that is a huge plus as the Maya documentation is excellent and i hope his input makes quite a splash.

But i will keep digging and hope that i am wrong on some of my first impressions.

The pose state also had me confused!!!!

Oh, i must of just had a bad day, i'll try again.

As you have had some experience with setting up in Maya, what do you think of character animation in Houdini in coparison with Trax in Maya. I know Trax has had a lot of criticism but some things are made so easy like looping walk cycles with the relative cycle parameter and also the ability to store clips. Also the fact that one can have all the Charater Set which contains all your animated bones together exclusive from non-animated bones.

Please tell me i have no idea the power of Houdini's character setup and animation tools with CHOPS being far greater Trax and Animation Mixer(XSI) in all ways!!!...only if it is true that is.

Betty

ps: if you can, do yourself a favour and checkout Mirai - HEAPS OF FUN!!!

[Jason]

I must say that I have am quite impressed with the character tools added in 5.x. A lot of the power still remains with the more power users when you get used to the freedom of manipulating your geometry before Capture, after Capture and after Deform. The Deform SOP is really quick too. A complex character I had simply rigged in Houdini had faster interaction than in Maya.

I am not a character animator, I am an effects person so most of what I see is more technical exploits of the character system, not the one-click-easy all-in-one solutions.

I think the Pose operation is a great tool indeed. It's designed to just be another manipulator which invokes the bones' natural handles instead of the standard Transform handle. The bone handles belong to the type of skeleton system and so it will provide you with a cool IK handle if it's an IK chain.

The Follow Curve solver does follow the spline correctly does it not? As far as I remember right now, that it remains bound to the curve, no mattter how you animate that curve.

Houdini has an operation called "Objects" (as opposed to "Select" or "Pose") which allows you to select many objects at once and get their local handles. This is not quite the "move one and they all move" kind of tail example you are talking about, but it does allow you to have many handles up at once and quickly move between them.

But you're right - the tutorials are all-important. Do you have the one PDF from the website: SESI tuts

CHOPs is obviously far more powerful than Trax will ever be, but it's major drawback is that it's geared to do so much more than motion compositing that the interface is pretty general. It doesn't have nice clickable tracks you can drag about et al. This is a real serious tool:) Of course any system which is specialised to cater for nice GUIs for limited actions like clip blending and looping can have an easy-to-use interface.

I'd say give Houdini character a fair chance and maybe you'll begin to see potentials's with it that are not available in other software without a ton of support coding.

With that, I have tried some pretty basic characters and I found a couple of annoyances (but that was during the beta-cycle and they've fixed those problems) but I was pleasantly surprised by the Dopesheet and supporting channel tools. It's come a looong way since 4.x and I picked up a good speed animating with a Dopesheet and the Pose state.

What is the general impression of the various character oriented tools out there?

Cheers,

Jason.

[betty]

Hi Jason

Great to hear such a positive reply. As i said, i did just start out learning the character tools and they were my initial impressions. And of course i would have no doubt that CHOPS are far more powerful an editing suite than TRAX. I have used CHOPS in other projects and love them, i just can't get my head around how they are used in character animation.

Yes things like Trax and the Animation Mixer are nice and simple and effective for what they do and i guess that is why so many people use them and like them. Because it is simple and you get the hang of it very quickly. And i think everybody would agree the tutorials are simple but great because they show you how to do most of the basics and then you run off and add/experiment with your own creations. If you are talking about the PDF with the Hoodnik set up tutorial, yes i do have it - but am i asking for too much when i say, "can i have some more?".

I will learn those damn tools and i'm sure i will love them, as i do with SOPS and POPS which i am fairly familiar with. And when i finally have things going i'll try and get a bloody tutorial together.

Best Houdini wishes

Betty

[Marc]

And when you do, give it to us . We'd love to host it for you...

Marc

[plan9]

Would deffinately be awesome to have more character setup/animation tuts...

I enjoy seeing other peoples techniques eg. VEX tuts by Jason helped me quite a bit, actually wrote a simple shader afterwards

The new downloadable movie tuts are priceless, Thanks Peter, more pls!

(or maybe i should get up off my a$$ and make some too )

Lub,

The Cap'n

[danteA]

betty,

... hmm ... follow curve kinematics works for me. what doesn't work though is animating the first point of the curve. for that, you need to write a point expression for the translates of the chain root object.

as for rotating all the bones at the same time, you might be able to do this if you use the Transform state to get a transform handle on all the (No Kinematics) bones. what you then do is right-click on the handle and there's some option to turn off the treating of all objects as one selection. I don't have houdini at home so I don't remember what the name of the option is. After that, if you rotate, then it will individually rotate each object in its local object space.

i agree that mirroring poses or from one side of a skeleton to the other is tricky in houdini without some set up first. how did the workflow go in mirai for doing this? rigs are pretty complicated things for the program to figure out what's the corresponding mirror bone. esp. if you've got special controllers for everything.

dante

[betty]

Hi danteA

I think i spoke too soon when i made my comments on the character tools as they really were my first impressions, it is not like i was playing with them for a week to get a fair idea. I also think i have been spoiled from doing bi-pedal character animation in Mirai.

I also think it is wrong of me to expect different tools to be work is similar ways, and god knows i don't want that or else there would be no Houdini. The thing is i have done basic character animation in XSI as well and it does seem easier with quick results.

I just have to do more work on it. By the way i just modeled a lo-poly head which i now plan to animate ( if anyone can tell me how to put an image on here i will post it ).

OK, with mirroring in Mirai it went something like this.

If you had a human character and wanted to move the left arm,

*first pick the upper arm bone

*you then have a choice to mirror or reverse mirror the movement. so for a jumping movement where both arm are moving in unison you simply choose mirror. So you just place and keyframe one arm while the other updates automatically. Obviously reverse mirror is for walk, run cycles etc, etc, where the arm is going the opposite way.

*once you have your character in a walk pose you simply save this pose. then you mirror the pose and move it into place. hit keyframe and your done.

It is very easy and efficient.

I'm going back to Houdini character tools now and i hope to get back to this board with more positive news soon.

Betty

[DaJuice]

Hey betty, you can upload your images here, that's what I used (the image will stay there for 6 months before it gets deleted).

http://207.164.141.121:82/

[danteA]

hi betty,

I also think i have been spoiled from doing bi-pedal character animation in Mirai.

Does this imply that Mirai have very special smarts built into their bi-pedal skeletons? Could all these tools you mention be applied in to general to any type of skeleon?

*first pick the upper arm bone

*you then have a choice to mirror or reverse mirror the movement.

So let's say you pick the left upper arm bone, how does Mirai know which object is the right upper arm bone? It seems like Mirai has a super bi-pedal skeleton set up already done for you? For example, if I created an octopus-like skeleton with only three tentacles in Mirai, would it know which is the mirror tentacle?

thanks,

dante

[betty]

danteA

Regarding the three-tentacled octopus, Mirai knows the mirrored bone/s when you initially set up your skeleton. As in Houdini with a simple character you build one side and then "mirror" the other side, hence it is easy to know which is the mirrored bone. Well i did just try the three tentacles but "I" couldn't get it going as the mirror is on one axis. But this got me thinking it would be great if you could "triple mirror" or something and the tool then gives you three bones which all "mirror" each other, like a copy with 120 degrees between each other but being able to work together, ie - mirrored animation/poses, weighting, etc. Maybe SESI could implement something like this.

The other thing is - i have hardly touched Mirai since i started Houdini and was only using it for a relatively very short period of time, so who knows maybe you could do the three tentacles.

Re;"..speacial smarts built in..." well i don't know what it has built in, all i know is that it is fast and efficient.

I have been actually making headway into Houdini's character tools but have fallen sick so am away from work for a few days. But i do have a bunch of questions, i'll wait to get back to work so i can have Houdini in front of me and i'll fire away.

Hope you have some answers for me!

talk soon

Betty

[Thirdeye]

Hi Betty

I have been using Houdini for character modelling and animation for a couple of months now (I'm a Max user normally) and I think I might be able to help here.

Regarding moving bones together. Say you have four bones labelled bone1 - 4 and they are linked together. Select bone 1 and right click and hold on the word 'Rotate' in its parameters menu (this applies the operation to all 3 fields, rather than choosing them one at a time). Select Copy Parameter from the menu. Now select bone 2 and right click on its 'Rotate' field. Select Paste Copied References. Now rotate bone1. Bone2 should rotate as well. Repeat the paste function in the other bones 'Rotate' field. If you have a long tail you can have the first three bones being controlled by the first bone and then another three being controlled by the fourth bone and so on. You end up keyframing maybe three bones to manipulate 10 or whatever.

Now to do this in chops (so you can animate with sliders) is a little trickier.

Create a new bone chain of four bones. Name them bone1 - bone4.

In chops place a constant chop and change 'chan1' to 'Tail Up Down'. Now place a fetch chop. Change the Op to ch (from the drop down list), change path to ch1, the second path to constant1, and in channels write value0(value zero). The channels in your constant chop are named value0 to value39 regardless of how you name them. Where I work we make custom VEX Chops so everything is named whatever we like. Now append a math chop to the fetch. Under Multi-Add put Multiply up to about 20. You can play with this figure later on. Append a merge chop to the math. You are going to need 4 channels (this slider will manipulate the rotation in x of each bone) so link the math into the merge another 3 times. Middle click on the merge chops icon to see if you have 4 channels. Finally, append a rename chop to the merge and in the 'To' field write bone[1-4]/rx. Click on the export flag on the rename chop and look at the parameters for your bones. If all goes well the rotation x field should be orange. This means it is being overridden by chops. Go to your constant and move the Tail Up Down slider(middle click on the value to access negative values). The bones should now move up and down. If they don't, look carefully at what you wrote in the rename chop. The brackets should be the square type and there should be no spaces.

We use this system to blend between IK and FK, or blend between a wave or oscillator chop and FK and so on. I can't go in to too much detail but this should get you started in chops. You can copy and paste this heirachy and change the fetch to value1 (put a name into the value1 field of the constant so it works first) and the rename to /ry and so on to do the other axis.

I really hope this helps you Betty. The power of Chops is quite extensive, it just requires experimentation which is what Houdini excels in fortunately. Let me know if you have any queries, I'm always willing to help. There are other ways to do what I've just explained, so experiment till the cows come home!

Ian

[betty]

Hi Thirdeye

Just read your post and went through all your advice and of course it worked beautifully, thanks heaps for all your help. Yep, all you said was so simple but opened up so much...like you said -experiment.

I suppose i have just spent more time in other tools and my way of thinking obviously hasn't changed over just yet.

So tell me how have you adapted to Houdini's character tools in your move over from Max?

Thanks again

Take care

Betty

[danteA]

Cool technique, Thirdeye! It guess that even though using CHOPs is a bit heavy handed if we're only doing tail a up/down, it might pay off in the long run if we decide to blend between different animations.

[danteA]

hey betty,

yeah, I agree that an arbitrary mirror option would be cool. for now, we can just mirror the bone chain and then by changing the pivot on the mirror chain's transform handle, we can rotate it into the appropriate position, and then do the same again for each bone chain.

as for mirroring weights, there's already the mirror capture weights operation.

dante

[Thirdeye]

Hi Betty

Glad to help. There is a lot you can do with chops that although it can take some time to build, it ends up making animation so easy that a person who doesn't even know how to turn on a computer could animate a character (so long as you turned the computer on for them).

This is what we are working towards with this children's show we are working on. We have fish characters who have a swim cycle powered by chops that can blend smoothly into forward kinematics control and/or inverse kinematics in the one shot. So the characters position is keyframed through the master null but the swimming motion is running on automatic. Then it is keyframed off over a period of frames and you can manipulate the character with sliders. Chops controls nearly all of our characters movement. We can also switch between inverse kinematics to forward kinematic controls at the touch of a button. We end up with a bunch of custom named sliders and buttons for all the parts of the character.

As for switching from Max to Houdini? Painful. I hated Houdini at first, although I quite enjoy using it now. I still find it clunky when it comes to building a rig but it gets there in the end. I still use Max, in fact in two weeks time I'll be working on two separate childrens shows using Max on one and Houdini on the other, thankfully in the same building. I will probably go mad though. But thats ok, character animators are allowed to be a little touched in the head. Helps with creativity. He heh.

Betty, try making that chop network again but with a wave chop instead of a fetch. Place it next to your existing chop network for the tail and put them both into a blend chop. Put a constant chop in (must be first in the list of the blend). This controls the blending. The blend should be proportional. Just be sure that the rename is the same and that both networks have exactly the same number of channels. You can do the same with the IK chop, just make sure the number of channels is the same.

Hope you have some fun playing with this everybody, Ill be sure to pick all of your brains in the future.

Ian

[betty]

Cool stuff

I've been playing around and with good results, looking forward to what's going to develop over the next few weeks.

CHOPS has so many possibilities which really makes it an exciting thing to explore.

Betty