zdimaria Posted October 31, 2011 Share Posted October 31, 2011 Hello I have an object, that I fractured by scattering points and then feeding those into a Voronoi Fracture SOP. They are being grouped into the default piece*, inside and outside. I then cached this geometry to disk. I then bring this object into a dopnet with RBD Glue Object DOP, with the group mask set to piece*. My problem is, whenever I run this sim, random pieces will stay together throughout the sim. And I dont mean glued together. These pieces are not adjacent, and can be on the opposite sides of the original geometry. It might be hard to see in these pictures, but these two pieces are definitely not touching. This is one example of what I am talking about, but this has happend across multiple sims, with different objects. I'm too new to say that this is a glitch, but I just cant seem to figure out what I'm missing. Zak Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 31, 2011 Share Posted October 31, 2011 Is that happening inside your DOPs? I mean when you view your DOPNET, do u still see that problem? Quote Link to comment Share on other sites More sharing options...
zdimaria Posted October 31, 2011 Author Share Posted October 31, 2011 Yeah. Thats a screenshot of the viewport inside the dopnet. I just turned off the visablilty of the static geometry to help show what I was talking about. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 31, 2011 Share Posted October 31, 2011 (edited) Have you tried bringing your geo to DOP before ROPing it out? Edited October 31, 2011 by ehsan parizi Quote Link to comment Share on other sites More sharing options...
zdimaria Posted October 31, 2011 Author Share Posted October 31, 2011 I have, and have had the same problem. I am also not ROPing it out, just geo -> scatter -> voronoi fracture -> filesop. then file-> rest ->dopimport -> file (to save simed geo out). I know if I used the shelf tools after bringing it in as a bgeo.gz to make it a rbd glue object, it doesnt understand that I've already fractured it, and trys to again. But I'm setting up the dopnet by hand. Quote Link to comment Share on other sites More sharing options...
Erik_JE Posted October 31, 2011 Share Posted October 31, 2011 I am pretty sure the pieces that are sticking together but should be separate are in the same piece group. This have been caused by that the site point for the voronoi have been positioned in such a way that both the separate pieces belongs to it. Turn on the visualization of the voronoi fracture and change the seed of the scatter until they have different color. Alternatively use a higher res fog volume to make sure that the points are only being scattered inside the actual geometry. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted October 31, 2011 Share Posted October 31, 2011 I have, and have had the same problem. I am also not ROPing it out, just geo -> scatter -> voronoi fracture -> filesop. then file-> rest ->dopimport -> file (to save simed geo out). Well, yeah, you use file sop to write your geo on disk, which is basically what ROP output does, so, what if we get rid of the file node?just bypass it. I know if I used the shelf tools after bringing it in as a bgeo.gz to make it a rbd glue object, it doesnt understand that I've already fractured it, and trys to again. But I'm setting up the dopnet by hand. you mean when you select your fractured object and then select the rbd glue object from the shelf tool, it doesn't work? Quote Link to comment Share on other sites More sharing options...
zdimaria Posted November 4, 2011 Author Share Posted November 4, 2011 Thanks for the replys, sorry it took so long to get back - I've been trying everything I can think of but these sims take quite along time. I am pretty sure the pieces that are sticking together but should be separate are in the same piece group. This have been caused by that the site point for the voronoi have been positioned in such a way that both the separate pieces belongs to it. Turn on the visualization of the voronoi fracture and change the seed of the scatter until they have different color. Alternatively use a higher res fog volume to make sure that the points are only being scattered inside the actual geometry. The pieces are all in their own groups, and the points are only scattered inside the geometry. I think what is happening, although I could be entirely wrong, is that an RBD Fractured Object just makes a bunch of rbd objects (pieces) glued to one big idea object. As collisions happen, they fall off of this object, instead off off of eachother. Is this correct or am I still very mistaken? Quote Link to comment Share on other sites More sharing options...
Erik_JE Posted November 4, 2011 Share Posted November 4, 2011 I don't know the inner workings on how Houdini does Glue but it seems strange that it would allow pieces to "float" around when they are not connected to the rest of the object. Do you have any hip-file that you can share? Quote Link to comment Share on other sites More sharing options...
zdimaria Posted November 5, 2011 Author Share Posted November 5, 2011 Not at the moment due to filesize, (unless you want to sim it out for yourself ), but I will try and reproduce it in a simpler fashion tonight or in the morning. Quote Link to comment Share on other sites More sharing options...
ehsan parizi Posted November 6, 2011 Share Posted November 6, 2011 Are you using only 1 voronoi fracture in your sop? Quote Link to comment Share on other sites More sharing options...
zdimaria Posted November 6, 2011 Author Share Posted November 6, 2011 Yes only one fracture. Quote Link to comment Share on other sites More sharing options...
DanBode Posted November 6, 2011 Share Posted November 6, 2011 When using glue with RBDs in Houdini, each object can only be glued to one other object. The RBD Glue Object glues all of your pieces to a place holder, not to their neighbors, as you were expecting. This can cause pieces that are not touching to be glued together, since they are both glued to the same place holder object. If you jump inside the RBD Glue object, you can actually see an Empty Object and an RBD Fracture Object, with the glue on the RBD Fracture Object set to the empty object. Quote Link to comment Share on other sites More sharing options...
dangerweenie Posted November 18, 2011 Share Posted November 18, 2011 I had an issue with the clustering attrs once, though they usually involve pieces that are adjacent. Have you figured this out yet? Quote Link to comment Share on other sites More sharing options...
odball Posted July 17, 2013 Share Posted July 17, 2013 New to forum so apologies if this has been resolved. I'm experiencing this same behavior. Has anyone got a solution to this? Cheers. Quote Link to comment Share on other sites More sharing options...
DanBode Posted July 17, 2013 Share Posted July 17, 2013 You can try using a glue constraint network instead of the RBD Glue object. This will cause your rbd pieces to actually be stuck to their neighbors instead of an invisible placeholder. This was added in houdini 12.0, which I believe came out after the discussion in this thread. Quote Link to comment Share on other sites More sharing options...
odball Posted July 17, 2013 Share Posted July 17, 2013 Buggy both ways I'm afraid. Tried to do the same simple example sim with glue object and glue constraint. Still get these odd bits hanging in the air :z buggy_RBD_glueObject.hipnc buggy_RBD_glueConstraint.hipnc Quote Link to comment Share on other sites More sharing options...
rwf Posted July 22, 2013 Share Posted July 22, 2013 Hi, When using the glue constraint network you will need to turn off the glue in your rbd fracture object. Your root object (box_passive) then needs to be included in the glue constraints network as well. If you don't (turn off the glue) then there is always the chance that some pieces will still be attached to your box_passive object. The fact that they are not adjacent is then irrelevant. I have attached a fixed file with these things working. Cheers, Rog. buggy_RBD_glueConstraint_fixed.hipnc 1 Quote Link to comment Share on other sites More sharing options...
odball Posted July 26, 2013 Share Posted July 26, 2013 Awesome. Thanks Rog! You setup seems to work. I'll play around with it more when I have time. Thanks a lot! Quote Link to comment Share on other sites More sharing options...
odball Posted July 26, 2013 Share Posted July 26, 2013 Darn. Seems that even this doesn't come without draw backs. If you set the glue constrain strength too high it will just start ignoring collisions. Oh well... Quote Link to comment Share on other sites More sharing options...
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