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Poser - OFFICIAL F.A.Q (Last Updated: 2024 Nov 18 10:25 pm)



Subject: Dynamic Cloth Question.


jwhitham ( ) posted Sun, 14 March 2004 at 1:54 PM · edited Tue, 19 November 2024 at 9:36 AM

file_102402.jpg

Hi,

I'm trying to make a beach caftype umbrella flutter in the breeze. First attempt it just fell through the spars and flew from the pole like a flag. Now I've added some vertices (shown above) to the constrained group, it doesn't do anything at all :(

Have I overdone the constraints or something? All cloth settings are on default BTW.

TIA

John


PhilC ( ) posted Sun, 14 March 2004 at 2:06 PM

Is the frame a figure or a prop? If its a prop I'm not sure that Constrained will work, try putting those same vertices into the Choreographed group. Another thought would be to quad subdivide the cloth. This is not causing your problem but may give more realistic motion when the correct procedure is applied. Finally are you sure that you wind fan is giving enough puff and aimed in the right direction?

philc_agatha_white_on_black.jpg


jwhitham ( ) posted Sun, 14 March 2004 at 2:30 PM

The frame is a prop, the first simulation did however react correctly against it to some degree; the spars deformed the fabric as it passed over them, and the whole thing remained attached to the top of the pole. That and the fact it did a pretty good job of waving like a flag suggests I'm not attempting the impossible, also that the wind is strong enough, doesn't it?

As to the lack of polygons, I know I should add some more, but the amount of to-ing and fro-ing I've done between different bits of software, just to get all the bits in at a reasonable scale, I don't feel like going back to the modeller and starting again!

I've got a feeling I've just done something really stupid somewhere, normally the case I find.

John


jwhitham ( ) posted Sun, 14 March 2004 at 2:55 PM

file_102403.jpg

OK, I had done something really stupid, somehow removed all vertices from the main (default) group. Tried again and acheived the above. I'd better learn how to make the frame into I figure I suppose, at least then I could make fold up - that'd be quite cool :)

John

PS Can vertices belong to more than one group?


jwhitham ( ) posted Sun, 14 March 2004 at 4:34 PM

file_102404.jpg

Choreographed Group seems to improve matters, a bit. Damn, but I'm going to beat this thing...

Oh, yeah, subdivided the mesh too.

John


nruddock ( ) posted Sun, 14 March 2004 at 5:42 PM

file_102405.jpg

Try using some or all of the Additional Collision settings, as the ribs look thin enough to allow the cloth vertices to miss them using the default settings.


jwhitham ( ) posted Sun, 14 March 2004 at 5:58 PM

Thanks, going there next. I'm a programmer, not a very good one, but if I know anything it's one change at a time or you don't know what caused the modification, could take a while but I'm going to get there.

John


diolma ( ) posted Sun, 14 March 2004 at 6:08 PM

I agree with "change 1 param at a time"!! (been there, suffered multpleparamchangeitis):-)) Just a suggetsion: You might try changing the elasticity, to overcome the drooping between the ribs? (just on its own, of course..) Cheers, Diolma



jwhitham ( ) posted Sun, 14 March 2004 at 8:22 PM

Elasticity meaning stretch resistance, fold resistance, density or a funtion of all three? You can't pass multiple changes off with me by giving them one nice simple name :)

John


Lawndart ( ) posted Mon, 15 March 2004 at 11:33 AM

Attached Link: http://www.3-AXIS.com

file_102407.jpg

jwhitham: Using the Choreographed group on the cloth is absolutely correct. 1. I modified two of the Choreographed sections circled in red. Do this to ALL the sections that need to match the umbrella stand. 2. Please Turn OFF all the collision options in the Simulation Settings. They aren't needed for this simulation and will just slow things down. I'll Explain in a minute. 3. I wouldn't use the umbrella stand as a collision object in the sumulation. It is not needed and trying to collide the cloth onto it will just take more time to calculate. (some of this is explained above in previous posts to this thread but I'll put them here so they are all under one umbrella) yuck yuck... OK... Why? The Choreographed group is used to exclude the verticies in that group from the cloth simulation. This means that any vertex that is in this group will not calculate as cloth so it stays in one place giving the appearance of being solid. Using this group in the way I show in the image will give the appearance of the cloth being held up by the wires in the stand. The actual STAND does nothing to simulate this. It is ALL done in the cloth object. That is why the stand should not be a collision object. It isn't needed. Another cool thing about the Choreographed group is that if you animate an object in the Pose Room and then use this feature in the cloth room the animation stays with the verticies that are added to the choreographed group. This means you can move an object around with parts of it flapping like cloth. This isn't needed for what you are doing but it is worth while to mention. Cause it's cool! :) The CONSTRAINED group is used with a figure for parts of the cloth that you do not wan't to calculate. A great example would be a belt that is part of a dress. You want the belt to be solid and the dress to be cloth. Any vertex added to the constrained group sticks to the closest actor of the figure that the cloth is parented to. In a nut shell, constrain group for use with figures, Choreographed for use without figures. I hope this helps, Joe


Lawndart ( ) posted Mon, 15 March 2004 at 11:41 AM

Attached Link: http://www.3-AXIS.com

One more essential use of the "Constrained" group. Imagine a skirt on a figure. If you put it on the figure and calculate the cloth the skirt will slide down the characters legs and fall off. By adding the top edge of the skirt into the Constrained group you have given it an anchor. In this case the anchor will be the hip or waist. Anywhere the hip goes the anchored part of the skirt will stay with it. This allows the skirt to stay up on the figures waist. Cheers, Joe


diolma ( ) posted Mon, 15 March 2004 at 3:40 PM

OOps, jwhitham - by "elasticity" I meant "stretch resistance" - but I think you're in better hands thain mine, given the intervening posts.. Cheers, anyway, and hope you get the problem sorted (I'm interested myself), Diolma



Lawndart ( ) posted Tue, 16 March 2004 at 1:17 AM

I hope this didn't sound like I was hijacking the thread. I would be mortified if I stepped on any toes. I don't think I did but I just wanted to make sure. I have used cloth a lot. It is frustrating and fun at the same time. With long bouts of calculating inbetween. :) diolma: Your adjustment to the "Stretch Resistance" to increase or decrease the droop IS A GREAT ONE! I will use that tidbit a lot. It is amazing how you can use something for a long time and think you have your way figured out. Then someone comes along and says something that makes you smack yourself in the forhead with an open palm and say "DOH". All the best, Joe


diolma ( ) posted Tue, 16 March 2004 at 2:30 PM

LOL, LawnDartx2 - my experience with the cloth room tends to be one of 3 things: o - It works 1st time. This is rare. o - It works fine after a few goes, if you tweak this and pull that. Most of the time I have an inkling of which dial to play with, just never know by how much or in which direction (and I always forget to write down the settings). This is fairly common. o - I end up with either a frozen poser (with the cloth-room in an infinte loop), or a confused mass of jumbled mesh with poke-thru, poke-in, poke some other way and similar mesh mess-ups (hmm. Try saying "mesh mess-ups" 3 times quickly..:-)). This is usual. VERY occasionally, I stumble on something that works.. Cheers, Diolma



jwhitham ( ) posted Tue, 16 March 2004 at 5:20 PM

Well, I'm extremely grateful for all the help I've been offered in this thread. I really do have an understanding of the cloth room's dynamics now, that dozens of readings of the manual never gave me.

Good news is; adding all vertices in contact with the frame, to the choreographed group, did what I wanted. Bad news is; my fabric cover mesh is crap - which, to be honest, I already knew but was hoping to get away with - so it's back to Anim8or to make a new mesh, probably not till next weekend now though.

Again, many thanks all for the help.

John


jwhitham ( ) posted Tue, 16 March 2004 at 6:02 PM

Oh yeah and, 'choreographed = static' - ie excluded from the cloth dynamics - did sound a bit perverse to me at at first... but as creating a rigid form, maybe umbrella ribs, maybe the bones in a bat's wing, with cloth simulation following... perhaps I should give up on my beach cafscene and go for gothic horror... Hmmm...

John

PS Or what about a beach umbrella that morphs into a vampire... descisions, descisions, life's a beach isn't it?


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