Hey All,
I’m probably diving into the deep end too soon, but all of Houdini so far feels like the deep end, so why not?

(Note: I’m coming at this from a Product Design using Solidworks direction, my training as an Industrial Designer merges Art and Engineering but involves no IT or programming knowledge whatsoever. As such, it feels like I’m attempting to learn to fly a plane by sitting in the cockpit of a 747 and all the controls are labeled in Latin. The multiple references to helping “artists” in the literature makes me laugh and remember the horror in the eyes of some of my fellow student when told they’d need to use math when learning to draft perspective views. Ah the bad old days. But I digress.)

So while I struggle to learn Latin (i.e. nodes and expressions and what CHOP VOP and SOP etc. acronyms stand for) and work my way through the really basic tutorials (hooray, I’ve managed to import geometry and assign materials!) I thought I’d pick the brains of live people, because frankly searching the online manual and reading the forum posts hasn’t been as helpful as I’d hoped.

So the project is to demonstrate liquid being swirled around in a vessel (like a drinking glass) spinning at 250 rpm.

The liquid simulation part is what got me excited to try Houdini in the first place as other “rendering” packages can offer basic movements of parts, but can’t actually change the shape of any geometry. What is odd, is that I can’t find what I’d think of as a simple function: rotate/revolve at X-rpm. Shouldn’t this be simple? Don’t even know where to start! It almost seems like setting up the container and letting the software figure out the turbulence of the liquid in it is better spelled out in various tutorials and videos than this basic function is.

Is spinning something just so stupid and basic that no one thinks to cover it as a topic?

Please help. Thanks.
-GW

Huh, I was hoping for a more active (friendly?) community…

Even someone saying, “hey Noofus (that's Noobie and Dufus combined) try looking at so and so's tutorial or so and so's video.” would have been nice.

I'm not looking for THE answer, just direction.

So far I've found that inputting $F into rotation generates spin, and of course I can increase or decrease by multiplying it, but the spin starts from frame one no matter which frame I put his expression in. Need to be able to spin it up and then back down.

Thoughts? (anyone anyone?)
-GW

You can enter a rotation value and add a keyframe from either the right button menu or by clicking alt+left button. Then you can go to another frame and do the same with a different value, creating animation. Or, you can click shift + LMB on the parameter to get to graph view where you can draw a curve for the rotation. (“scope parameter” in right mouse button menu.

And yes, these are very basic topics, you could try the “Basics” section of the help, http://www.sidefx.com/docs/houdini13.0/basics/ [sidefx.com]

There's a great selection of learning material in the Learning menu above.

Check it out, a lot of those questions like animation ease in and out, and X-rpm seem to show that the fundamentals need to be established first.

Head to the Getting Started under that Learning menu. The next step will be to post a project file where you tried to make it but something just isn't working.

Good luck!

Thank you to all who responded. I may have shamed some of you into it, but as someone who’s self taught in all the programs I use professionally (Solidworks, Illustrator, Manga Studio to name a few) and who has taught college students to use both Illustrator and Vellum, I know the incredible value of being able to ask a living person for guidance. Think of yourselves as Houdini Sherpas. I plan on climbing Everest (Houdini) myself, but even getting guidance on what to pack before I get there is of great value. Yes, the guides and videos are terrific, but as my students would say, “if I don’t even know what words are being used to describe what I want, how am I to look it up?”

And as basic as my questions are, the resolutions are not as simple as they might seem. After all, I can key frame rotational positions and generate an expression to create spin, but as soon as I start smoothing transitions out in the channel editor, the functions become Bezier curves(functions) and I no longer have my RPM formulas at the key frames. Clearly I need to figure out how to have a constant slope, with an RPM formula and on either side have ease in/ease out Beziers. I’ll eventually figure that out, but clearly I’m already in deep math waters…so not so basic after all.

For the moment I’ll table the RPM problem in favor of seeing if I can apply Peter Quinn’s Wine Spill methodology to get my liquid swirling in the glass. Hopefully I won’t make as many mistakes setting that up! So many ways to go wrong!

Anyway, thanks again to those who pointed me in a direction (or at least confirmed I was heading the right way) and please be patient with us new users. You all started at the beginning at some point and this particular program isn’t the best for self instruction.
-GW

I think a lot of folks are just busy a lot - there aren't many zillion post users in the forum, but when they are about they're extremely helpful - sometimes to the point of doing your job for you so don't fear about engagement.

Re learning the ropes, I don't think I've seen a tutorial yet that hasn't been informative in some way, even if it's just affirming things I thought already, or showing another way of doing something that I already do a lot myself.

If you're dead set on learning Houdini, cmivfx.com have a lot of material and regular 40-60% off sales, or an all-you-can-eat subscription. Video quality could be better (this may just be my location) and it's not all current…seems to go back to H11… but the tutorials are a decent length (up to 8+ hours) and you can absorb a lot of core knowledge and techniques from them, which I think is usually more important than a simple “how do you do that”.

Enjoy anyway…the fun never ends with Houdini, which is probably the real reason nobody's posting!

There is a general principle in the cultural landscape that is known as Houdini land; posting project files will gather help than writing long posts.