I decided to turn to Houdini inspired by Forms [vimeo.com]. Given that I am completely new to Houdini, but I already have the motion tracking data as multi-segmented spline, what tools/concepts should I study to create the following:

1. Generate particles emitted from the positions, which move along many spline segments concurrently.

2. Generate geometry such as pipes, nurbs, driven by the positions moving along many spline segments concurrently.

Links to relevant tutorials would be especially helpful, as well as the highlevel concepts and speculations.

Thanks a lot.

My multisegmented motion tracking spline looks like this:

6 days, 93 views, 0 answers. I guess Houdini is not the right tool for this job?

I think there's a certain ‘seek and ye shall find’ quality to any answer to your questions… Yes you can do all of these things, and it can come to you quite quickly if you get stuck in with the tutorials…it's a deep a bit hole and there's no one single answer; there's no shortage of info on where to start, but for creative input/discussion you could pop over to odforce.

A couple of like minded random links from there…

http://forums.odforce.net/index.php?/topic/8471-eetus-lab/ [forums.odforce.net]
http://forums.odforce.net/index.php?/topic/16470-machas-sammelsurium/ [forums.odforce.net]

The forms stuff is really cool btw.

AdamT
I think there's a certain ‘seek and ye shall find’ quality to any answer to your questions…

Thanks for your reply and links, I will study them. I am browsing all the tutorials and posts here, which sound like they could teach me what I am after. However, a problem I am having is that although they sound applicable, due to Houdini approach, which is completely foreign to me (coming from c4d world), I get lost very quickly without ever answering the question, whether I could do what I am after at the end.

Long story short, these are more concrete questions:

1. How can I dynamically run a constant length sweep nurb (c4d term) along a spline.
2. My spline has lots of segments (again, c4d term). In c4d I can iterate through the segments using xpresso, and use them as standalone splines in a loop. Can I do the same in Houdini (I don't want to break my spline into individual splines before bringing it into Houdini, since it will complicate the whole workflow, which is now C++ => C4d => Houdini.

Thanks again.

Pirate smell is very strong…

Houdini's not so different as people sometimes imagine; it's easy to get bogged down by all the operators and the UI, but under the surface all 3D applications do the same things. The hardest part here is that you have to think for yourself a little bit more - that's the price of flexibility: fewer canned effects. Think of Houdini as a sandbox - lots of toys, and lots of freedom to build stuff with them… but it does take perseverance and a lot of patience, and sometimes you have to unlearn old habits to learn new ones.

Bo Ba
1. How can I dynamically run a constant length sweep nurb (c4d term) along a spline.
2. My spline has lots of segments (again, c4d term). In c4d I can iterate through the segments using xpresso, and use them as standalone splines in a loop. Can I do the same in Houdini (I don't want to break my spline into individual splines before bringing it into Houdini, since it will complicate the whole workflow, which is now C++ => C4d => Houdini.

Sweep SOP. Mantra can also render curves: see the Next Steps foliage tutorial for grass as splines.

Segments as you'll expect them are edges in Houdini. These aren't a specific geometry type like they are in other applications. You can access them, but they're a property of primitives (a quad primitive has 4 edges, which are described as point pairs). This is a little bit outside the bare basics, so I'd suggest working on mastering small things and work your way upwards (or outwards, depending on your perspective).

The attached shows sweeps, using particles and points as sources for curves - try plugging your curve into the network.

For further reading, I'd strongly recomment going through the docs, which are pretty good (could be better) and can orient a new user to the systems and concepts of working in Houdini.

For modelling fundamentals in particular:
http://www.sidefx.com/docs/houdini12.5/model/ [sidefx.com]

@AdamT: This is extremely helpful. Thank you very much.