OK, I think I'm finally getting the handle on Houdini, I have a few questions related to Character tools though.

Is there any analog in Houdini to Maya's wrap deformer, and Maya's influence objects. I'd like to try to build a muscle rig, so if anyone could just rattle off the names of some features to look up that would facilitate this, I'm all ears.

And a general question. I'm running Win 2K Pro SP 3, and a decent computer, Athlon 1400, 512 megs of PC 2100 RAM, and a GeForce 3. Houdini uses significantly less system resources than Maya, and for the most part runs great, but I have a few little problems. Houdini often redraws the entire interface when changing modes or adding a generator or filter or whatever. All the icons along the top of the pane kinda flash and redraw themselves, and I can't do anything for several seconds while this is going on. It's very annoying. I always get memory errors when quitting Houdini, no big deal, just annoying, and working through the Sub Division surface tutorial posted here (the knife) I found the extrusions to be very sluggish, even while making the first extrusion from a simple 6 sided cube. Is there anything I can to to eliminate these problems and improve performance?

Hi Michael,

Perhaps you could give some more description of what those Maya features do? Try looking up the lattice sop which allows you to deform by using boxes as well as arbitrary geoemtry.

The other sops that will probably come in handy are: metaball, bulge, magnet. One thing to note is that bones in houdini are pretty much simply geometry objects with some extra parameters which means that you can put extra sops inside bones to help with deformations. One way is to put metaballs inside your bone object, object merge the metaball into your skin object and then apply it to the skin using bulge.

Another advanced use for bones is to animate the capture region parameters for deformation. As well as putting multiple capture regions inside bones (merge them all and name the merge sop, cregion).

Perhaps someone who has done it before will help answer some questions on building muscle systems in Houdini. (Ken, are you there?)

Finally, your computer system sounds fine. Since you're running on a GeForce 3, make sure you're using the latest detonator drivers. I've heard of users experiencing problems with the nvidia opengl drivers slowing down horribly when they have apps that always stay “on top” of all the other windows. I've also heard of reports that the “Draw Lines Smoothly” option is unuseable on geforce cards without the softquadro patch. I hope this helps.

It sounds like the lattice SOP is a good substitute to the wrap deformer. The wrap deformer is pretty much a lattice deformer that allows you to use arbitrary geometry.

I'll take a look at metaballs and bulge. I know what metaballs are but have never actually used them. Should be interesting.

Thanks for the help, Edward. Anyone else who has experience with muscle rigs fell free to pipe up. I'd like to know what all the options are, and if anyone has any clever tips or pitfalls to watch out for.

EDIT: A quick explanation of influence objects in Maya for those who don't know. Basicly you place pieces of geometry that are either rigid (to represent bones) or animated or driven through deformers or expressions (muscles and tendons) under the skin of your character. You make these muscles and bones influence objects for the skin, and they will deform your character's skin as it animates to simulate bones protruding and muscles flexing.

For Wrap deformer, you can use CurveClay SOP for it. It works like charm for me so far.

yah ed i'm here..

there are a few interesting ways to go about doing muscle systems in houdini.

you can go about it like any other package and use a series of bones and capture systems to obtain some deformations. you can also make a series of models and plug them into a SequenceBlendSop and use a combination of the fit expression (exhelp fit in the textport) and the bone angle expression (dido). here's great tip i use a lot.
drop down a FontSop and use the backquote-single quote ` around the expression in the text field. the expression will be evaluated and you will get the result (`boneangle(“/obj/chain_bone1”, “/obj/chain_bone2”)`

the fit expression will allow you to get theses numbers into a useable 0-1 range. be aware the boneangle expression is not limited to just bones. you can use a null to obtain angle information to use as well.

just remember that you have the opportunity to tweak and work on you character before it is actually captured and deformed. so depending on how you build it you can add extra deformations to the mesh which will carry through to the finished model.

-k

Try installing the latest TCL/TK libraries aswell. It made Houdini significantly quicker, at least for me.

(I suggest getting ActiveTCL. Since it's quite easy to install, easy to find and supports also all the modern extensions).

That seems incredible - I didn't think that that should make a difference! Has anyone else seen this?

Is hwish based off the latest version of Tk?

jason_iversen
That seems incredible - I didn't think that that should make a difference! Has anyone else seen this?

Is hwish based off the latest version of Tk?

I suggested this over at OdForce aswell. And it seems to work for people, including for you now

no- i haven't tried it myself.. perhaps i should..

jason_iversen
no- i haven't tried it myself.. perhaps i should..

Oh, my bad. I thought you did.

hum, i realised that i already have ActiveTCL installed, so i can't tell if i got sped up or not..

can anyone from SESI corroborate this?

I am a long time mac guy. After taking a class at SESI, I was so impressed with HOUDINI that I bought a new HP. I have little to no experience with the technicalities of the win2k OS, but I am determined to become a HOUDINI power user.

So what is active TCL and do I need it?

Houdini often redraws the entire interface when changing modes or adding a generator or filter or whatever. All the icons along the top of the pane kinda flash and redraw themselves, and I can't do anything for several seconds while this is going on.

Try setting the env variable HOUDINI_OGL_DBL_BUFFER_FIX to 1. This might solve your redraw problems with the GF3