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Everything posted by dtarr77

  1. That's a good idea, i got it working pushing points along the u attribute with an offset and emitting from them but this may be more practical for fluid and art directed, thanks!
  2. Hi, I have an issue that I have not been able to figure out. I need particles/fluid to follow a curve, which I know how to do easily, but this particular curve crosses over itself a couple times so using Volume Velocity and Curve Force causes to particles to divert off by grabbing on to a later section of the curve. (ref images attached) Is there a way to restrict them to the current section they are on so that they ignore the areas where the curve crosses over itself? I have not been able to figure out a way to do it so I thought maybe the amazing Houdini brains on here might have an idea? Thank you in advance for any help/suggestions you can offer!
  3. Yea, I'm using volume velocity node to push them along because curve force wasn't giving me the look I needed. I tried animating the carve node but if any particles get too far ahead or behind they just stop because they aren't being affected by the velocity/force anymore but if I use a point lookup the look breaks down. A friend suggested looking up the u attribute to follow with an offset so I'm looking into that too.
  4. Hey Noobini, I got to check out your file, thanks so much for sending it! It's a different way then I was getting it to work which is always awesome to see alternate routes. Mine was using the SOP version but I like seeing the DOP side and how to implement it. I definitely learned a couple things looking at it like utilizing the break threshold with the constraint properties. I appreciate the help!
  5. Hello houdini wizards! I am playing with Vellum and trying to get the dynamic glue constraints to work. The documentation is about 1 very small section and I did what it said to (like creating the glue inside the solver and setting the Create Constraints drop down to Each Frame) but it does not grab the cloth. I played with distances and groups but no luck. I don't have a specific scenario at the moment so no scene file really that cant be set up in 2 minutes, just a grid as the cloth object, a sphere (fed into the collision input at the sop level) that dips down close the grid and then moves back up. The intention is to have constraints be created to grab the cloth within the set distance, pick it up, pull it, and then release/break the constraints when I want/need to. The breaking I can assume is pretty simple using the broken attribute in the Constraint Properties but I cannot seem to dynamically create constraints to grab the cloth/grid. Any help or knowledge you can give is much appreciated! I was unable to find any example files on the subject either but I did see the demo of it being done (https://vimeo.com/313872854) around 24:50. And again, thanks in advance for any advice you can give!
  6. Hey Noobini, Thanks for replying! I'll check the file out when I get back to my computer on Monday.
  7. So I got it to work due to my coworker coming across Rohan Dalvi's recent tutorial that I missed where he is able to get it to grab an object and release it. I was able to use the vellum constraint property node to release it more manually using vex but it is a bit frustrating that to have the object grab the cloth it has to be an actual vellum object within the simulation where the cloth could potentially collide with it. If anyone finds a way to get it to work without the glue object being able to collide with the cloth or vice versa please do not hesitate to post. I will post an example file below of my simple test just in case it is useful to anyone. glue_RnD.hip
  8. Hey Guys, I am trying to learn how to create a flock or boid system and going through the CMIVFX Tutorial about it. I realize it is a bit out of date at this point but I wasn't finding a lot of tutorial stuff on boids and flocking. In my file it seems like the forces are working correctly individually but when it gets to the steering part of combining the forces it seems like something is messing up. The flocking points should move towards the arrival/attraction point while trying to avoid each other but instead they head towards it and just keep on going. My guess is that the forces are overwriting each other, possibly due to the steerCount attribute. I am not sure what is going wrong though to cause that. In the tutorial they use the import() function which I found was deprecated now, so I used the pointattrib() function instead to get the attrib. So either that is the wrong substitution for it or it's some small thing I am missing between the versions that is not working like I think it is but I am still learning Houdini at an intermediate level. I also tried messing with the priority value but the tutorial still has both set at 1. I have attached the file to jump into and labeled in the VEX where the import() functions were used. I hope it is easy to tell what is going on in the file. Thank you in advace for any help/advice you can give. flockTutorial_v001.hip
  9. Hello, I am working on a project helping a friend where I have a fractured character/object (made of a cloth like material) that is basically disintegrating and blowing away using the spring SOP with help from a CMIVFX Tutorial The only issue is that I need the pieces to dissolve away to nothing as well. I figured the "foreach" node (with a transform node shrinking as time passes with $FF) would be the way to go, but I am still learning Houdini and VEX expressions, and despite any research, I have not been able to really understand how to get it to do what I want. The foreach node still kind of confuses me at the moment. How can I get each piece to shrink way over time to nothing? Thank you in advance for any help. Thanks, Dustin
  10. Hi guys, Currently, I am working on a project where I need a way to get a fractured geometry cloth simulation to activate each fracture piece according to the color attribute. The plan is that a curve, representing the path of another object's motion, will pass through the fractured object causing it to begin floating away and disintegrating from the point of impact/contact. I am still learning Houdini and have only been working in it consistently for about 6 months or so, but I have the effect mostly working with the disintegration and cloth simulation and such. What I can not seem to figure out is how to activate the pieces as the color envelopes the object. I have found other forums posts that have given some good routes (That's where I got the color transfer route to where it is currently at) but they are for fractured RBD objects and I have not been able to get those to work for a cloth object in DOPs. I have the color working in SOPs but just need help getting that into DOPs and controlling the activation of each piece. I have created an example file and attached it below. Thank you in advance for any help/advice you guys can provide. Thanks, Dustin P.S. As a bonus problem solve: one piece seems to get stuck on nothing, as if it is constrained to an invisible point in space, but it has no constraints. I am not sure why yet. I'm going to keep looking into the issue, but if anyone knows why please let me know. Thanks. ClothFracture_Test.hiplc
  11. Fractured Cloth Activation By Color Attribute?

    Juraj, I just went through the file, that is amazing! Thank you so much! This is exactly what I was looking to do. I would have never thought of the Geometry Wrangle with my current level of experience but it makes perfect sense. I applied it to my scene and after some tweaking to fit it to the situation it looks like it is working. Thank you again Juraj. It is a HUGE help and very educational as well. Thanks, Dustin
  12. Motion Vector Pass h14

    Hi, I don't know if you guys are still following this thread or not, but I was wondering how that hip file works? I am pretty new to Houdini and trying to get a motion blur pass out of it, but setting it up like yours does not seem to work. Does it only for alembic files? Does this work for particles? OR Is there a way to get a motion pass from a particles render? Thanks, Dustin
  13. Fractured Cloth Activation By Color Attribute?

    Hello Juraj Tomori, Thank you for replying, I am going through your example file and trying to adapt your process to my situation, but I am running into an issue where the "test" group node (named "release_grp" in my file) inside the SOP solver of the DOPs network is not liking the $FRACTURETHRESHOLD != 1 expression. I have tried my best to keep it as similar to yours as my particular situation will allow but now I think I am in over my head a little. As far as I can tell, the only thing that MAY be essentially missing, or different, is my route of fracturing. I do not have the fracturepart attribute due to using voronoi fracture because I did not like the solid fracture results for my situation. I do not know if that matters, but I thought maybe I could convert the name attribute for my pieces to the integer attribute of fracturepart like in your scene. Unfortunately, I have not found a way to do so outside of an expression that I do not know how to apply yet. The POP force also does not seem to want to see "release_grp" group inside of the SOP solver. I tried with a working group (no expression) and it still does not see it. At the moment, what simulation is happening is very strange an erratic. So I have a few questions: - How do I convert the name attribute (string type attribute I believe, right?) of my fractured pieces into the integer attribute, fracturepart? OR - What am I missing that is causing this not to work in my scene? (see attached example file of my test scene attempt at your process) - If I use your route just to get the color attribute in like my original idea, how do I tell a dynamic group node to only use color? It seems the expression area of the "Group Dynamic Objects" node works much differently than the SOP group node, and the "Active Value" node does not see any group nodes inside of the SOP Solver nor the original SOP geo. It does seem to see color now, but I do don't know how to call that up in the group or Active Value node with my currently very limited scripting/expression skills. I will be very grateful for any help you can provide. Thank you again, Juraj. Dustin (Also, if you are able to look at the file, beware of the visualize energy node, seems to almost crash Houdini for some reason if you try to play or skim the timeline. Possibly due to whatever is keeping it from working.) ClothFracture_Test_v02.hiplc
  14. Hey Dennis, The Assemble node is exactly what it was needing. Also, after looking at your sample file, I was putting in the name "pieces" in the foreach node instead of the actual attribute ("name"). I knew it was probably some small thing I was not realizing was wrong with setting the foreach node up. I really appreciate the help Dennis. The spring sop is still acting funny, but I am sure that just needs some parameter tweaking to get right. That file was a huge help in actually seeing how it should be set up. Thank you very much to both of you for your help. Dustin
  15. Hi ofog, Thanks for replying. I have tried the Centroid equation in Pivot. Sadly, this just put the center point to the centroid of the entire geometry as well. So the whole object shrinks to it's center while it is disintegrating instead of each piece shrinking. It doesn't seem to be picking up the fact that there are pieces, only one big object. I have tried messing with the different foreach methods but none seem to make much of a difference, but I do not know if I need to set something up in advance for those aside from the group option. I will try to set up a simple proxy scene with a sphere with similar settings maybe so that I can put up a file.
  16. Hey Dennis, Thank you so much for replying and the expression. That expression helps, but the biggest issue I am having now is that it scales the fractured geometry as a whole to its centroid point (which is near its base) instead of each individual piece getting smaller to its own centroid point. It is more than likely that I am not setting up the foreach node correctly since I am very new to it. I tried both the foreach subnetwork and loop versions. I figured Loop was not the one I needed, but tried it anyway and it does the same thing in this case. I do actually have particles within the effects working, but the director of the short film this is for, wants to have disintegrating pieces of the object/creature (kind of made of a cloth-like material) as well. I tried copying some distorted grids to the particles, but I have not liked the way that has worked out so far. Orientation has been an issue there, so I figured that the fractured object with spring sop would be a quicker, more efficient way within the timeline I have. (could be wrong) Unfortunately, I cannot put up a file since it is for a short film, but I have attached pictures of my node graph that I hope will maybe help. Any suggestions? I appreciate the help, Dennis.
  17. Hello, I have been learning how to create custom velocity fields and trying to figure out how to get my velocity to decay the further from the center it is. For example, my scene has a sphere who's normals are directing velocity along with a noise field. I want to have the velocity lessen as it gets further from the center of the sphere. I figured creating a ramp in a VOPSOP whose value could control that might do the trick, but I am still pretty new to VEX and VOPs and such. How would I get a ramp color to do this? If that is not a good route, what is the best way to achieve this velocity decay and control it manually like this? Thank you in advance for any help or advice.
  18. Custom Velocity Decay Question

    Actually, I think I figured out the issue. Just needed to play with the Fit Range node a little more. I was adjusting the wrong Fit Range Max values. I was increasing the Destination Max instead of the Source Max. I also had to reverse the spline ramp because it was decreasing in the center and increasing towards the outside. Seems like it is working now though. Thank you very much to both of you. I really appreciate the help.
  19. Custom Velocity Decay Question

    Thanks for replying Sean. That makes sense, I had seen that centroid expression in my searches, but had not known how to implement it here. I still have a lot to learn. haha Unfortunately, the vop still doesn't seem to be decreasing the velocity so there must be another issue as well, but that's one part of the issue solved. I will keep messing with it though. Thank you Sean.
  20. Custom Velocity Decay Question

    Hey dchow, Thank you so much for replying. I am pretty sure I understand the process you describe, but doing it is another story. I see a "center" output in VolumeVops (is that where this process should take place?) and tried your process according to your description but I don't think I did it right since it doesn't seem to be working. I looked at Attribute/Point VOPs and I did not see a center/centroid output. How do you grab that vector value? I have attached a screencap of my node graph inside VolumeVOPs.
  21. Hi, I am trying to create an effect where my smoke changes color depending on its age or lifespan like particles rather than temperature. My experience in Houdini is still pretty amateur and I have not found any way of doing this in my internet searches so far. I found one that mentioned using pcfilter and transferring particle age over to the smoke volume without much explanation. Unfortunately, I have never used point cloud filter and have no idea where to even begin to go down that route. I have played around trying to figure it out myself but have had no luck. I know this is an awesome Houdini forum community so I figured I'd see if anyone here might be able to offer some insight or help on this matter. Does anyone have any suggestions on possible routes to achieve this effect? OR Do you know how using the pcfilter as stated above might work? I have particles in the project that are using the effect I want to create with my smoke where they go from pink-ish to a light blue. So I have included a picture below that maybe will help explain better what I am looking for. Any help/advice you guys are able to provide will be much appreciated. Thanks.
  22. Hey Atom, Again, I appreciate the help. I went through the file and got it to work, but is not exactly the route I am looking for. Although it is still a very useful lesson I didn't know on creating attributes in volumes and such. So it is still a helpful file I will keep to refer to as I continue learning Houdini. What I probably should have stated in my first post to make it more clear on what I am aiming for is that I have a pyrosolver already working. The smoke is being emitted from a different set of particles (image01 below) and I want to implement age into that smoke. (image 02) That way I can create a similar color effect to the particles in the image of the first post.
  23. Thanks for replying Atom, I appreciate it. I will check your file out and try your process in my project file and let you know how it turns out. Thanks again.
  24. Custom Velocity Fields

    Hi, I am still pretty new to Houdini and have been trying to figure out how to create custom velocity fields as well. I came across this forum post and I started going through the pyroFX tut from above, but it is not working. It accepts the noise inside the Volume VOP but you do not see it affect the volume trail. The visualization is just straight lines at an angle. Also, when i add the parameter 'windirection' like in the video I get an error at on the Volume VOP node saying "Unknown parameter: 'windirection'." I have triple checked that it is set up like in the video and that my spelling is just like his as well so unless I still have missed something I am not sure what is causing it. Has something changed in Houdini 15 since the video was made that may be causing this? I know a lot of things have changed since houdini 13 and lower. I am only a few steps in (about the 24:06 mark) and have attached my file if it's needed. If anyone can lend any help or advice it would be much appreciated. Thank you.
  25. Hi guys, First time posting in here. I am a beginnner to intermediate Houdini user who is just recently diving into it deeply and just have a simple question about Uniform Noise at the Material level. Currently, I am going through a tutorial that is done in Houdini 13, I believe, on creating textures. They put down a uniform noise node in the Material VOP network and use a slider for "Exponent" to adjust what seems to be the contrast of the noise. I am using Houdini 15 and since things have changed so drastically since then there is no longer an exponent slider. I tried playing with the options that are there and messing with the fit rang (unclamped) node but nothing seems to get the same effect as in the tutorial which is one I would like to use for an idea in the future for padding. Is there something that replaced the exponent slider that I may be missing? Thanks in advance for any replies and help.