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mandark

Houdini Operators V/s Maya nodes

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Hi, I am new to houdini, and of course interested in learning it and also how to program it. I currently work with the Maya API and read the online docs of Houdini HDK help.

I had a question after giving it a casual read. In maya, i can write a node which can take in, say one parameter, and i can perform calculations on it and output say 5 parameters. This node can then be connected to attributes in a network.

While reading the help, i found the types of network and also the kinds of customizations possible in houdini. Theres, SOP, POP, COP, CHOP etc, but suppose i want to write a simple node (like the one i described above ) then are there any general type of operators to do so?:blink:

Another eg would be a node which takes a value and outputs it's sine(sin()), which can then be networked in any graph in maya.

Thanks...

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I had a question after giving it a casual read. In maya, i can write a node which can take in, say one parameter, and i can perform calculations on it and output say 5 parameters. This node can then be connected to attributes in a network.

CHOPS is where you normally do just that only you don't need to write the operations, They're already there, you just network them. For example, use the Fetch chop to bring in a parameter (channel) from anywhere in houdini, append a Math chop or whatever have you to perform your operations and then add any number of export chops to send this data anywhere else in houdini. any pre-existng channels just get overridden.

Another eg would be a node which takes a value and outputs it's sine(sin()), which can then be networked in any graph in maya.

Check out the Wave and/or Expression Chops

I suggest you go through some of the video tutorials at sidefx to understand this better

One of the big attractions to houdini is the fact that you don't need to code as much in houdini as you would probably have to in other packages

cheers

tallkien

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:D Thank you friend. I'm in the process of downloading the side fx videos. I wish if an apprentice edition of the HDK also become available! B)

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You're probably also going to want to take a real good look at VEX and VEX builder. Between VEX, CHOPs, and HScript, there's probably not much you would want the HDK for.

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Houdini is complex for sure. In Maya we can write a note which takes a curve as an input and output a surface (Eg: a loft command) . I hope Houdini has something in the same lines.

I think the HDK would also be useful to write something as somebody made that RealFlow->Houdini SOP. I want to do something in the same lines in my life. :)

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HDK not free.

But, knowing any programming language and having understood GEO specification,

you can make almost everything with help of Unix SOP

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Good Luck to you mandark

Just don't get ahead of yourself.

If you look at it, "Input -Operation-Output" is the very basis of working in the houdini gui. I'm also guessing you just love working in the script editor even if there's a tool sitting there on the shelf :unsure:

In your case it might help to think of houdini as a Visual Programing Environement for 3d rather than just another 3d app

btw you may feel closer to home with the Textport

cheers :rolleyes:

tallkien

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Houdini is complex for sure. In Maya we can write a note which takes a curve as an input and output a surface (Eg: a loft command) . I hope Houdini has something in the same lines.

Houdini has one of the most powerful skinning (lofting) tools around. Well, it did the last time I checked the other packages anyway :D.

You should check the geometry help and look at the skin OP. Its pretty versatile, and no programming needed :)

Cheers

Marc

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I don't think. that lofting of curves is the thing mandark is concerned of. The important fact is, that you can only modify atributes within VEX or VOPS. If this attribute coincides with the position of the vertices ("P"), you modify the shape of an object and thus implement a modeling OP. But there are many modeling operations, that either involve some topology-changes or the creation of new geometry. All this is not possible with VEX. You need the HDK for this task.

There are so many things you can do using a real API instead of a scripted language. Let me mention an example for Maya, I did some time ago: I have written a plug-in, which enables Maya to simulate 3D-positional sound and mix it down to a 5.1-surround-system. This is something Maya wasn't built for, but having the power of C++, it was possible to create new node-types that represent speakers and microphones and perform all the computations in an efficient way. This would be impossible with MEL.

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Well my point was, was that there are plenty of things you can do in houdini without resorting to coding.

I find that alot of people that come from other packages automatically assume that because you had to script/code it in another package you need to do it in Houdini too.

Because the lofting one was mentioned, I showed how you don't even need to go anywhere near code to do it.

And as for you example, CHOPS does all sorts of spatial audio really well. Mess around in there for a bit and you'll get something. Again, no coding.

Granted if you're writing plugins for external applications then you'll need to do some coding. Or if you know there's something you need to do that would be more efficient to write in VEX (as opposed to using a bunch of SOPS/etc.) then you'd need to code too...

But the immediate leap to coding is definitely not needed for most Houdini tasks.

Cheers

Marc

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Well my point was, was that there are plenty of things you can do in houdini without resorting to coding.

I find that alot of people that come from other packages automatically assume that because you had to script/code it in another package you need to do it in Houdini too.

Amen brotha!

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...

And as for you example, CHOPS does all sorts of spatial audio really well. Mess around in there for a bit and you'll get something. Again, no coding.

...

Yes, i know that Houdini has a great spatial-sound-system built in (Maya did not have one). I just wanted to make clear, that having the access to an API is much more powerfull than scripting or clicking together some OPs. I'm also aware, that the point, when you have to fall back on programming is much further ahead in Houdini than in other packages. I mentioned this example, because of a lack of Houdini-specific projects I made. The HDK wasn't delivered with my student-license :-(

Well here is an example, when you would need to use the HDK: Assume, that you don't need the provided Catmull-Clark-Subdivision, but another scheme like loop, sqrt(3) or whatever you like. In a package like Maya I could fire up the compiler and write a node, that performs this task. In Houdini I would have to buy a developer-license :-(

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Wow! I think Frank has hit the point. I was not talking about "lofting" as such. I ment a node capable of taking a "curve" data type and operating upon it to create a "surface" data type.

And yes, I sometimes prefers coding to be more convinient than visual graphing because contrary to the popular belief, it's mostly easy to go in and edit a code that looking at a complex network of graph in the Hypergraph. I know Houdini netwok editor is awsome. True procedurlism so things are arranged pretty neatly. But not in Maya. So this behaviour of mine must have been developed while working with Maya.

Nodes, I think are the most important part of my workflow. They are like lego blocks and I think a 3D software is only as strong as it's nodes! Thats why I want to clarify these things beforehand. So instead of asking "Does brand X has feature A", I often start with the nodes and their architecture.

Cheers! :D

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Guest xionmark

Very intresting thread, again points out the need for the HDK to be available with Houdini

(and Select, Halo, Escape), not at an additional cost. Regardless if there's already a solution in Houdini already,

one may have the need or desire to do something more or different than what's already provided.

This is certainly the case for me, I mean, how many Houdini users like to connect robots and wigdets and such

to their boxes and have Houdini playing the starring role in the center of it all ... not many, but a few.

There's just no logical reason to restrict the artist's (programmer's) creativity. A thriving 3rd party developer

community would be benficial to all Houdini users, SESI, and I suppose the CG community as a whole.

I don't know if there's an appropriate channel to voice to SESI your desire to have the HDK available "free",

maybe support@sidefx,com, not sure, maybe the SESI forum is better. I'm right there with you!

Maybe together we can help change this ...

Good luck!

--Mark

P.S. Hmm ... Anyone intersted in an HDK course ...?

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P.S. Hmm ... Anyone intersted in an HDK course ...?

I would be, if the HDK were free! :lol:

Seriously though, early on, I wanted to try and put together an geometry exporter. The only solution I could find without the HDK was to spit everything out into a text file and then parse that text file and output a binary file from a command line program. It'd be really nice to be able to make a proper exporter that worked directly from Houdini. I really think the HDK should be free just for this reason. In games, every project I worked on used custom model and animation formats. It just seems odd to me that a developer would have to pay so much extra to be able to do that with Houdini. Other than that I think Houdini has a marvelous set of tools for game development. There are things I can do easily in Houdini like creating and painting custom flags on geometry, and tri-stripping geometry, that are much easier said than done in other software. For instance, just flagging attributes, this was such a difficult task in past versions of Max and Maya that companies I worked for would run out and spend 20K+ per seat on Multigen, which is an absolutely horrible piece of software, just to flag geometry. If I had known at the time how easy it was to do this in Houdini I would've begged them to go that route.

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