Compositing & Houdini

[artwrx]

I currently use Combustion for compositing. It is the only software that I have ever used. I am starting a small effect shop for indie films and my partners are looking at using Houdini for modelling an animation. We want to be as seamless as possible as far as creating models and compositing to film. I know that Houdini has basic compositing capabilities but can anyone fill me in on its abilities as far as 3d tracking, color correction, keying, keyframing, etc. any sugguestions as to what compositing software works best with Houdini as far as file import/export and integration would be helpful.

[gdc]

Houdini can render out files to almost any format, so importing images that houdini renders into a compositing package isn't really a problem. Houdini's compositer can also read just about every format out there so, importing images into houdini to comp isn't a problem either. As far as the compositer in Houdini-it is very powerful and you can do most of what you need to do. I say most because there are some limitations. Currenty there isn't any tracking of any kind, no garbage masks and no paint capabilties just to name a few. However, I've heard that version 5 should address some of these problems.
Personally, I like to use houdini's compositer for working out the basic composit and doing pre-comps, but for final comps I perfer something that is a little more powerful (Flint, Inferno, ect). That being said, I know that there are companies out there doing final comps in houdini.
Hope that helps

--g

[artwrx]

Thanks for the info. Do you know if the people using Houdini for their final comps are using GIMP for painting? Also I know a couple of 3D matchmoving software packages that export camera positions in ascii format. Can Houdini import this file format? thanks.

[gdc]

I'm sure GIMP is capable of doing the painting you need, for the most part. My only hesitation in using something like that is if you need to paint, say multilple frames and not have them boil. I'm sure there is a way to do this I've just never had to do it. I've usally had acsess to a Flint or Inferno for this. Are you planning on using Linux? I only ask because you almost never hear of people using GIMP on NT, even though it's avalible.
For using 3d tracking software info in houdini, the short answer is yes.
The long answer-- Some packages, like 3D equlizer can export it's 3d track into many different formats which can then be read into their respected 3d packages. 3DE will write out a .cmd file that can then be read into Houdini. It will create a camera node and some null parent nodes that you then attach your object nodes to and presto! a 3d track for you camera/geo's.
I have also been able to use the ascii output of a flint track in houdini as well with the help of some scritping to get the info into a formated layout that houdini can read and make sense of. You can probably also do this with CHOPs.
If you can afford 3DE with the Houdini export filter I would go for it. I've been very impressed with what you can do with 3DE.

--g

[artwrx]

I'm planning on using NT for the software and maybe Linux for a rendering server. I don't have any experience compositing with linux or houdini, so I figured that learning houdini who be enough time and effort by itself. how powerful is the ipaint program that comes with houdini? I am used to working with
*paint plugged into combustion and I love it. I can't stand photoshop. the interface is easier to use for me. Anyway, I read that 3DE was a great program. How much is it? the cost of houdini is going to set me back for a while. I was asking about ascii because the boujou tracking software from 2d3 uses it to export info. Was the ascii script you wrote difficult or complicated? I wonder if 5.0 will include tracking? Do you know when it is being released? Thanks for your help. You're saving me a lot of time and effort.

[artwrx]

The sidefx website had some info on importing camera info which was helpful. A disscussion group suggested 3DE, Ras_Track,& Maya Live. Are you familiar with Ras Track or Maya Live. I guess Ras Track is Hammerhead's proprietory tracking software that they are selling. Can you buy maya live as a seperate product? Odforce.net is a cool site. do you know of any other Houdini users sites?

[dougr]

As far as I know Maya Live is not available as a stand-alone product. It is based on Synapix Synamatch technolgy. You can get Synamatch as a stand alone product.

Sign on to the Houdini List server from the sidefx site. It is very active and a lot of good information comes from there.

[gdc]

ipaint is pretty weak, IMO. It reminds me of what "paint" in windows could have looked like at some point in it's development. I'm not sure when version 5 is due out. Details on it are far and few between right now, but I do recall reading somewhere that the Compositer will have tracking. Can't say for sure if that came from SESI or not, so take it with a grain of salt.
Off of the top of my head I can't recall what 3DE costs. The range I seem to think it's in is the 3,000-5,000 range, but I could be way off. I looked around on their web site but couldn't find a price so you may have to contact them for a price. I know that they charge for the different export filters and they have a "video" version and a "film" version which cost different amounts. At either rate, what ever they charge for it, it's worth it!
As far as the scripts go--Thinking back on it they did only 2D tracks, but adding 3D to them should be that involed.
There are 2 different ways to approach this that I can think of.
The easier way would be to take the information out of the ascii file and out it into a .geo file format (basically a list of point posistions). In this situtation you would read in the .geo file and then create a poly line with it and use it as a path for the camera. This might work OK like this although we had to send it into CHOP's to smooth it out a bit. This should work for 3D as well, although I only used it with 2D.
The harder way to approach it is to parse the ascii file and convert the units it uses into Houdini units. This can get more involved and a lot more complicated. Flint for example can write out it's track as pixel offsets, so you know that the track moves X pixels per sample, so the trick here is to convert the pixel offsets into Houdini units. Then you can create an animation channel for your camera or null or whatever and it should match the track.
Like I said, what ever they charge for 3DE it's worth it.
Also like others have suggested, it's worth signing up for the Sidefx mailing list. You can sign up for it on their web site (www.sidefx.com). I belive it's under support.

--g

[artwrx]

Thanks for the info from everyone. I got on the sidefx mailing list yesterday. I realize that writing scripts is something that I will have to get used too. combustion doesn't have that ability in version 1.0. I have read that VEX is easy to use. I have been doing a lot of research on all the things that we have been talking about the last few days. The bottom line is that I would like to be able to do most of the things that I can do with combustion with houdini. Nothing special, basic things like creating alpha channels with masks, chroma & luma keys, and difference keys. I also need stabilization and 2D tracking, (I have resigned myself to the fact that I will have to purchase another piece of software for 3D tracking). I am sure houdini has no problem with the other things like shading, lighting, and cameras. I do have a question about color correction. Does houdini use histograms or curves for color correction? can samples of a color in a layer be picked and cloned. I also have a question about animation(keyframing) of layers. combustion and animate anything that has an operator. what are houdini's limitations?

[gdc]

Well, I think saying that saying VEX is easy to use is a little misleading. It is a programing/scripting language and because of that there is a learing curve. If you've used RenderMan to write your own shaders or have been using MEL or C, then yes VEX is pretty easy to use, but if you've never had to do any scritping, then it's not so easy to use. Thats not to say that you can't do it, just be perpared for it. As far as being able to do most of the things you do in combustion in Houdini, I wouldn't hold your breath. Like I said before you can't do alpha channels with masks,currently there isn't any stabilization or tracking. Also the compositer is sort of stange compared to a layer based system--it's node based, meaning that each operation you perform has a node that goes with it. For example, a simple composit of two images may be something like this:
File Node (bottom layer) File Node (top layer)
| |
| |
| |
Over Node ( where both images are placed ontop of eachother)

If you want to do something to one of the layers you would inset another node between the File node and the over node, then because Houdini is procedural the node down stream will update.
Color corection could be done with a brightness and contrast node. The contrast COP (node) gives you control over each of the channels with a slider. So it's more like a histrogram than curves.
Off of the top of my head I can't think of a way to pick one color out of a "layer" and clone it into another . The thing to keep in mind with houdini is that it's procedural so you don't do a lot of picking ( or pushing and pulling points) to get the thigs you want. You generally use one of the nodes to access the information you want. You can animate just about everything in Houdini, if it has a user controlable attribute then you can animate it. Houdini also has a very powerful expression language and an abilty to referance any chanel anywhere, meaning that it is possible to, say have the tx channel of a ball driven by color value of an image. This is a little extrem but it should give you the idea that you can do just about anything in Houdini. It's weakest point is probably the compositer, which is why they are giving it a lot of attention in version 5. One thing you may want to consider is to contact SESI and ask for an eval copy.
--g

[artwrx]

I am going to ask for the eval copy soon. A friend of mine is going to get an education copy that I can work with as well. I guess that I'm debating getting Maya Unlimited for about the same money ( maybe a little less) versus getting houdini learning and hoping that v.5 has the tracking, keying, color corrrection that I need. when you look at it you get maya 3, Paint effects, maya live (synamatch) 3D tracking software, and Maya fusion (although it is the LE version) with unlimited. What do you think ( In other words what is your opinion) a sidefx rep would say when I ask them why I should spend 17K on houdini and for 16K i can get Maya 3 plus at least 3 other programs that I can use. It would be different if 3rd party software plugged into houdini (like Ultimatte, Primatte, of 3DE). What do you think the possibilities of something like that happening are. I am trying to bulid a case in my mind that houdini is what I need but I need either a lot of faith in v.5 or some plugins to become available in the near future.

[gdc]

I can't really tell you which software is right for you.However I would think about a few things before you buy any software. I would think about what are you going to be doing most of the time? Are you planning on doing a lot of character animation or are you going to be doing a lot of effects type stuff? What tools do you really feel you need in a 3d package?
I'm sure if you ask a SESI rep they will push the strong points of Houdini, just like an Alias rep would push the strong points of Maya. I don't have a lot of faith in future releases of any software until I see it and get to use it. Untli then it's just vapor ware. Also keep in mind that even if version 5 has all the things you want many of them are going to be in there first version so there's always a chance that it doesn't do/work the way it should.
It sounds like you've used Maya already so maybe getting an eval copy of Houdini is the way to go before you commit to it. In the ultimate situation I think I would get some 3d package, a compositing package and a 3d tracking package and a rendering package (like RenderMan). Of course that's if money is no object!
--g

[artwrx]

that is great advice. I have been talking to my local reseller about those same issues. As far as what tools I need in a 3d program, I'm not the modeler in my company, I know just enough about modelling to get my self in trouble. I'm the compositing artist, so what is important to me is that I get the models composited in the easiest, fastest, and best looking way possible. That is why I was looking at one "suite" of programs that did compositing and modeling quickly and easily. As far as what we are concentrating on, we target independent films who have a lot of needs but a small budget. Most of their needs are effects and modeling, not animation. Since I currenlty use combustion and my partner uses 3D max, I am going to look at a combustion/max/mental ray package with the primatte plugin. I'm also going to look at Maya complete with Renderman, and Houdini with Chalice ( Chalice has the same node based style as houdini and has Ultimatte built in) the price of all are comparable and they are all great programs. i just want to pick a suite and go with it.