Hans Peter Posted January 4, 2017 Share Posted January 4, 2017 Hey guys, I'm struggling with the fem solver. Basically I would like to create a realistic looking cloth sim for the sails of a ship. Unfortunately I just can't get it to look right. The wind force deforms the object like animated noise insteat of adding variable velocity. I fit01ed nearly every parameter on the wind force or uniform force but it keeps looking like jiggly gum, not like cloth floating in the air. Can anyone show me an easy example on how to achieve something like this? https://vimeo.com/136480165 [vimeo.com]this is how my gum looks like: https://vimeo.com/197677800 [vimeo.com]Thanks! Quote Link to comment Share on other sites More sharing options...
Atom Posted January 4, 2017 Share Posted January 4, 2017 SideFX does offer a dynamic sail asset for free on Orbolt. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 4, 2017 Author Share Posted January 4, 2017 Hey, thanks for the hint but actually I got it looking better with my own setup ATM :/ But still can't get to look like in the example video. Quote Link to comment Share on other sites More sharing options...
Guest tar Posted January 5, 2017 Share Posted January 5, 2017 they are using Maya nCloth - hopefully H16 improves things but you'll save a lot of hair by using nCloth until then. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 5, 2017 Author Share Posted January 5, 2017 So you think its again something with the FEM solver? In the houdini forums we had another problem where we just couldn't get a very simple effect with some curtains. Unfortunately I don't know maya at all but something like this just can't be that difficult to achieve with Houdini. Strange thing. Quote Link to comment Share on other sites More sharing options...
Guest tar Posted January 5, 2017 Share Posted January 5, 2017 If you are familiar with Big O; then getting results with nCloth is logarithmic, whilst Houdini is currently quadratic. Not saying it can't be done but... Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 5, 2017 Author Share Posted January 5, 2017 (edited) Nope, sir. No idea what you are talking about. Anyway, are there some plans to improve 'this'? I wonder, because I read a lot that Houdini's cloth system is quite good. Probably the wrong source. Edited January 5, 2017 by Heraklit Quote Link to comment Share on other sites More sharing options...
Guest tar Posted January 5, 2017 Share Posted January 5, 2017 FEM cloth is a work in progress; the theory is that it will be spectacular, interacting with all the solvers and using attributes etc Best to check your source's examples IMO Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 5, 2017 Author Share Posted January 5, 2017 Hopefully a soon happening spectacle. Do you have some experience with the grain solver for simulating cloth? A first test isn't looking too bad. Of course I have to see how it looks with some applied forces. Quote Link to comment Share on other sites More sharing options...
Guest tar Posted January 5, 2017 Share Posted January 5, 2017 Not enough experience with the pbd solver - marvellous designer does everything I need. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 5, 2017 Author Share Posted January 5, 2017 I'm surprised, it looks really good and actually like wind with a pop wind; and not rigit noise deforming a grid. Just need a way to constrain that stuff to other objects. Quote Link to comment Share on other sites More sharing options...
Guest tar Posted January 5, 2017 Share Posted January 5, 2017 nice - to pin it create a 'mass' attribute and set it to 0 on the pinned bits. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 5, 2017 Author Share Posted January 5, 2017 Yep, worked. I should have tried this stuff earlier. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 6, 2017 Author Share Posted January 6, 2017 I took a closer look into this sail asset from the orbold store. There is a way to apply custom external vel forces to the drag model of the cloth object. I tried to reproduce it but the velocities aren't affecting anything. Hopefully someone sees the error in the file. I can't find it. vel.hiplc Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 7, 2017 Author Share Posted January 7, 2017 (edited) So in case you are interested in further playing with it here is the hip file. Seems like this is the propper way to add velocities to fem cloth in houdini. I'm already getting some waves propagating through the cloth and its behaving much more lose than with other forces. Basically I imported some custom vel field from sops. The tweaking of the noise mainly determines the shaües you get. But the probably most important thing is to reduce the strength of the tangent and and normal drag considerably. Still needs a lot of tweaking but it finally works. vel.hiplc Edited January 7, 2017 by Heraklit Quote Link to comment Share on other sites More sharing options...
stickman Posted January 7, 2017 Share Posted January 7, 2017 Heraklit, Very cool scene to dissect! If anyone has time for some questions: - I tried to create a group for the attachment points to speed up the process of defining these after updating geo resolution. 1) a group node has no "select" or "update selection" option, I found no way to reactivate the content and so just made a new group node. How would you experienced users do this? 2) I first made the group node in the Sail item, then realized it has to be in the DopNet. But cut/paste doesn't work from one to the other, and making a new one only gave me the option to create an item group. So, I would make a reference of the selection, right? Sorry for very noob questions. Trying to feel out the mindset. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 7, 2017 Author Share Posted January 7, 2017 (edited) If I understand you right you want something like this? This expression will gice you the points on top. Edited January 7, 2017 by Heraklit Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 7, 2017 Author Share Posted January 7, 2017 Actually referencing them in DOPS is a problem. I tried a point and npoints expression but without any luck. Quote Link to comment Share on other sites More sharing options...
Hans Peter Posted January 7, 2017 Author Share Posted January 7, 2017 I only need the point numbers itself. Is there a way of accessing them in the node? Then you could reference the numbers in dops I guess. Quote Link to comment Share on other sites More sharing options...
Sepu Posted January 7, 2017 Share Posted January 7, 2017 just put the Group name on the clothattachconstraint1 Quote Link to comment Share on other sites More sharing options...
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