Hair dynamics, wire, rope and hose

[McNistor]

Hi!

I start this thread to discuss a little about hair in XSI and how can it be used for other purposes than... well organic hair.

I've seen once a video tutorial for Maya while i was visiting a friend -a Maya fanatic- (art of rigging if i recall) and that guy (in the video) used Maya's hair to simulate some wires on a spider like robot.

Not a long time ago i've tried smth similar to achieve in XSI. No luck with hair. I've used one script which simulates a wire out of a curve. The problem with the script is that it doesn't keep the initial length of the curve and the more stiffness you "put" the longer the computation gets (smth simlilar to cloth simulation).

In the above mentioned video-tut i remember that the instructor converted some curves to hairs and pined the end points attached to some robot's parts.
Now that xsi-ess has hair (which is great), more users have acces to hair. Making hairs out of curves rather than popping them from a cluster or poly-object deprives you from simulation.

Will we see some hair improvements in the next versions of XSI? My guess is that we will, but the Q is what version. Will it be 7, 8 or 9? Who knows... the sooner the better.

I'm not a simulation expert and have little experience with Hair simulation. Maybe there are ways of doing ropes, wires and hoses in XSI but i might not be aware of.
Please post solutions or just your thoughts about current XSI's hair implementation and why not, how would you like the future improvements to be.

Regards

[3dtutorial]

I hate to say this (but I will) XSI hair dynamics are well.... horrid.

They are in need of massive improvement in my opinion.

J

[Adrian Lazar]

rope dynamics please please pretty please :D i need it for the cables on the robot that I'm building now :D
If others (http://www.sidefx.com/index.php?option=com_content&task=view&id=971&Itemid=266) can than Softimage can to. As others have said, a character doesn't just sit in a corner naked, it must interact with his cloths, hair etc...
Right now I'm looking for a solution to simulate cables and it's a nightmare so far...

[kim aldis]

http://kim-aldis.co.uk/drupal-6.1/node/10

[Adrian Lazar]

Hey Kim,
Thanks for the link, I tried the plugin some time ago but i didn't get a good result. I'll try it again (harder) for my current personal project.
Still, i would like to have a dedicated solver for rope simulation that ships with xsi.

[kim aldis]

there's no reason you shouldn't get good results with it; I've never had trouble and most people find it straightforward. If there were a 'dedicated' rope simulation it would be either rigid body or cloth based, both of which are already in xsi. I don't really see the point when the tools are already there.

[scaron]

@kim

i tried implementing rbds into character rigs with out much luck. three issues came up...

if you try to drive the initial state parameter you get lots of broken sims
if the initial state gets values in a certain range you get broken sims
if you use mocap on your character you get volatile sims

all which make the simulation useless. all of these issues i have been working hard on coming up with proper examples for softimage to hopefully improve them some way...

steven

[KrisR]

I agree, XSI is in need of some sort of simple, quick way to make dangle-y bits and antenna type things. Having a single hair strand as a curve that you could deform geo to would be nice. I've seen things like this whipped up in Maya a dozen times with such ease and I cringe whenever I have to resort to Syflex (AWFUL) or RBDs (overkill) for something similar.

[Adrian Lazar]

kim, look, i've setup in no more than 2 minutes a rope pinned at both ends simulation that collides with a rbd in houdini where i am a total beginner. I don't know what exactly is underneath their rope simulator solver (i'm guessing chains of rbd) but at first sight it works fast, stable it's easy to setup and has some specific parameters like rope thikness. And that's not the case with XSI. I have no doubt that with some scripting skills you can do all that but not everyoane knows how to script that or the interest to learn scripting for something that should be introduced as default.

[kim aldis]

All I was saying was that most people who use it found it easy to set up ropes with the rope-building script. You don't particularly need scripting skills to set something like this up, the original version was done by hand and the script itself is just a time saver. In my opinion it's also a reasonably well-functioning answer to your request for a rope tool; if an official one were to be addes to XSI I doubt it would be very different in principle to this one, the methods used for simulations of this kind are all much of a muchness.

If you have a problem with the tool maybe it would have been better to contact me rather than, against all the evidence, complaining that it doesn't work.

[mde]

Make a nurbs strip, apply Syflex (or maybe even normal cloth) and extract a curve from it.

And yes, there are 3 things I miss in XSI when I switch from Maya, dynamic curves, nCloth and, recently, muscle system.

Hopefully XSI will catch up with dynamics in near future.