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Found 20 results

  1. fit mass for bullet

    Hey! I have a bunch of pieces from a fractured geo, and I plug them into a rbd bullet sim. I have very big and very small pieces, which is fine, but the problem is that if I let the rbd packed object to calculate the mass obviously I get very different mass result (and that is absolutely correct), but you know, sometimes we don't want exactly the real thing so is there any way of fit the mass so after is calculated I can fit it to more suitable values? I was trying to find a way of setting the mass in the fractured pieces and turn off the calculation in the rbd packed object, but I'm not sure if there's a way of calculating the mass at sop level... thanks!
  2. How to Calculate @w to Aim RBD Object

    As I'm just starting to understand quaternions and orientation in Houdini, I'm not sure how complicated this is to achieve. I could be completely over thinking it. Ultimately I would like to create a force in dops to rotate the packed object to its current direction of motion, or it's velocity. Modifying @w seems to be the best way to do that. For a first step, I'm trying to make a setup that takes a rbd packed object and rotate it back to it's original orientation. While it technically does that, it doesn't do it logically. It flips around its axis in bizarre ways. As I understand, it's behaving erratically because it's trying to rotate around all of its axes at the same time. This is the code I'm using in a pop wrangle node: vector qToE(vector4 q_value){ float q_0 = q_value.w ; float q_1 = q_value.x ; float q_2 = q_value.y ; float q_3 = q_value.z ; vector out = {0,0,0} ; out.x = atan2(2*(q_0*q_1+q_2*q_3), (1-2*(q_1*q_1+q_2*q_2))) ; out.y = asin(2*(q_0*q_2-q_3*q_1)) ; out.z = atan2(2*(q_0*q_3+q_1*q_2), (1-2*(q_2*q_2+q_3*q_3))) ; return out ; } v@euler = qToE(@orient); @w = -v@euler*1*{1,1,1}; This is where I got the quaternion to euler function: I've attached my houdini file to this post. If anyone has any tips, I'd be very happy to hear them! Thanks! orient_rotate_v01.hip
  3. Is it possible to create two way collision between rigid body and grains? I am trying to make a simple example where a sphere is dropped down in a container of grains.
  4. Hello, could someone explain to me what this parameter does exactly? What is being sampled for tolerance?
  5. Hi, I'm trying to get a rigid body destruction simulation working in Unreal 4 as a vertex animation using the Game Development Tools. I've got it looking pretty good in game now, except some of the pieces tend to randomly flip briefly as they rotate. It usually looks wrong for about a single frame or two. I've seen similar problems in sims from Maya, and it's usually been some sort of gimbal lock or euler problem. I'd usually be able to fix them by turning on unwind curves, applying a Euler filter, or by hand if it was just a few pieces. What is the best way to deal with this in houdini 16, especially with a large number of pieces? Is there a filter I can apply to the animation curves? Also (sorry, I'm still new to houdini), where would I access the animation curves on a file cached sim? Thanks in advance! Brian
  6. FRC tool for concrete fractures

    Hello everyone! This is the first demo of a new tool I've been working on in Houdini. The idea is to simplify the process of adding steel reinforcement in concrete fractures, specifically FRC (fiber reinforced concrete) My aim is to produce a single node that takes your simmed geometry and adds these steel fibers along the fractured surfaces. Here are some examples of my tool so far: password = vfx Current controls: - max fiber length - randomize fiber length - max angle (before fiber breaks from the adjacent piece) Things I plan to add: - randomize max angle - fragments of concrete stuck to fibers (as seen in example video below) - fiber straightness (how straight/crooked the fibers are) If you have any cool ideas or suggestions, or feedback on my work so far, let me know! (The idea was inspired by the following breakdown video at 2:39)
  7. Hi everyone! I'm relatively new to Houdini, and I came across a tutorial which explained the bullet solver for H13. I am trying to recreate the effect that he got at 53:15, where primitives were deleted from the constraint network when a force over a certain threshold was applied. tutorial: As I understand, the SOP solver was changed in H14, and I therefore don't have the object merge node that he has. I downloaded the example HIP file and copied his node into my own project and managed to get it working, however I'd like to know how it actually works, rather than just copying and pasting! The data that the node is bringing in, is as follows: `stamps("..", "DATAPATH", chsop("relnode") + ":Relationships/" + chs(chsop("relnode") + "/relname") + "/" + chs(chsop("relnode") + "/relationship/dataname") + "/Geometry")` This isn't like anything I've come across so far in houdini - if anyone knows what this means, and could explain it I'd be very grateful! Best, Stephen
  8. Hey everyone,My overall goal is to simulate liquid poured into a glass with ice cubes inside, with the ice cubes floating.Everything works normally until I enable feedback forces: Normal: https://gfycat.com/LameCarelessIzuthrush With feedback: https://gfycat.com/FlashySolidFreshwatereel There's a ton of particle loss. For these sims, particle separation is 0.004, grid scale is 2, feedback force is 1, and max FLIP substeps is 10.The best I got was to maintain volume with 1.75 grid scale, but with overreacting ice cubes: https://gfycat.com/MiserlyEmbarrassedAfricanbushviperI've attached the Houdini file for this below.Anything related to this problem would be helpful. Why is there particle loss, even without reseeding or with many substeps (I've tried using 20)? Is there a problem with how I'm using feedback? Why does changing grid size cause volume to increase or decrease?Thanks! ice-tea-milk_027_017.hipnc
  9. Hi everyone, I am new to Houdini, so I want to ask such a question. In previous versions of Houdini when I created RBD objects from a node (which has inside several objects), it handled the node and its contents as whole, but in Houdini 16 it is different, I mean it handles its contents as individual pieces. I guess it is due to that Houdini 16 creates an RBD packed object. How can I achieve so it handles the node as a whole?
  10. Houdini Tutorial VOL 01

    Houdini tutorial VOL 01 Houdini Training Package number 1: Educator : Amin Sadeghvand | Software : HOUDINI 15.5 | Level : Medium | Duration : 13 hr | Volume : 4.31 GB| Quality : HD | Language : English . Website
  11. hi guys i'm having a bit of an issue here - i've got a rbd sim using bullet and a glue constraint. Basically a bullet passing through an hour glass... overall its working really nicely and sims nice and fast. However theres some chunks that sit on top of the larger unbroken piece at the bottom. I cant suss out how to refine the collision of this shape sadly so what i want to know is if its possible to use a goal for the simulation - i'm fairly sure i've seen this done many moons ago... I want to be able to take the pieces on top of the unbroken chunk and sort of force them and move them out of the way... so the simulation tries to work towards a final resting position? I hope i'm making sense here? ta ant
  12. hi guys i'm having a bit of an issue here - i've got a rbd sim using bullet and a glue constraint. Basically a bullet passing through an hour glass... overall its working really nicely and sims nice and fast. However theres some chunks that sit on top of the larger unbroken piece at the bottom. I cant suss out how to refine the collision of this shape sadly so what i want to know is if its possible to use a goal for the simulation - i'm fairly sure i've seen this done many moons ago... I want to be able to take the pieces on top of the unbroken chunk and sort of force them and move them out of the way... so the simulation tries to work towards a final resting position? I hope i'm making sense here? ta ant
  13. RDB Data baked to Points

    Hey guys, So lots of info about using points to setup a RBD sim - but im looking at going the other way. I wish to take an RBD sim and collapse it to points. The point would probably need to store at least Position, Scale, Velocity and Rotation. I have done a packed RBD sim and using the packpoints SOP I get my centriod points out with P - but would love a bit of guidance in getting the other data in there... or if I am going down the wrong path completely. The objective is to take an abc out of houdini without geo - only point attributes to use in another package. I found this... http://blog.sina.com.cn/s/blog_7ecf408b0101pnyq.html He's doing exactly what I need, but can't work out how it's being done. Any help appreciated. Cheers, Ollie
  14. Hey guys. I'm trying to figure out a destruction setup for things like fences, wooden frames, plywood walls (that thin stuff thats really easy to put a hole in accidentally) etc. The part I'm stuck on at the moment is how to mimic things that are nailed together. Specifically, how to set it up so that when the fence/frame/whatever is hit by something, it doesn't just break apart, but instead just becomes a slight bit loosened, causing it to wobble a bit and fall over slightly. I realize that explanation probably makes little to no sense, so I've included two reference images. One depicts the effect that would happen for an entire fence, the other is for a single beam. I've got an example scene that uses the Cone Twist Constraint. It it gets me part way there, but is obviously way to static, and just stops suddenly. What I would like would be some subtle wobbling, as well as the beam the rotate down abit (to mimic the photo with the horse). I had the idea of using a Glue constraint with a bit of stretch. Problem is, I have no idea how to get a glue constraint to stretch (or if its even possible) and I couldn't find anything on Google about it either . Is anyone able to point me in the right direction for figuring this out? I'm still struggling to understand constraints so any guidance would be extremely helpful Nailed_Wood.hipnc
  15. This roadblock stemmed from this thread that was started here. I thought, wow, this is awesome, you can do so much - such as fracturing. However, when I tried to just do a very quick "let's see if this works" setup in my DOP network by adding a Voronoi Fracture node; it ignored it. <~This was using a Packed Rigid Body Object (I've attached my scene file without the voronoi node). However, when I switched the Packed Rigid Body out with a Standard Rigid Body object, it fractured. I've been trying different methods to the best of my new abilities to get this to fracture, but I can't find an answer or figure it out. I took Matt Estela's setup from his site posting here and tore it down to it's barest of bones. In short, I'm trying to get the spheres to fracture on impact using the packed rigid bodies that are emitted from the POP Source. Blah, this forum is the best. Thanks for any help you can give. fracture_test.hipnc
  16. Hey guys I have done inner and edge displacement on my fracture pieces ,it looks fine but while rendering cracks are visible before it happen see in the below image Note: (I have done the fracture pieces and displacement manually not with voronoi fracture node) Thank you
  17. Hi Guys, I really need help with this. What I have is a complex Truck rig coming in from animation. Its got multiple moving parts and some parts need to break apart as it gets hit and collides with objects. I have managed to fracture the object and transfer the animation back onto the frags via a nice matrix transform setup I found on Odforce. The trouble I'm having is how to bring animated frags (packed primitives) into Dops and how to control them becoming active either on collision or at specific frames. The other thing I cant figure out is how to get the active pieces to be still glued or constrained to the other animating non active pieces. Presently I'm trying to achieve this with Packed Prims as I have alot of pieces and its lighter in Dops but I have tried doing it the old fashioned way with Deforming RBD Fracture objects, but I still have the problem of Controlling when objects become active and then constraining them to the non active animated pieces. The best way I could think to illustrate this is when the windscreen shatters its still constrained to the non active window frame so that it continues along with the moving truck. I have attached a super simple truck file that's been cleaned up off my tests, as none of them are working anyway. I would really appreciate any help anyone can give me on this, Its driving me crazy not being able to figure this out. Cheers.
  18. Hey guys, I've been trying to solve one problem I have with RGB applying to voronoi pieces, which are driven by particles. So in the beginning I create a box and voronoi it, create centroid point for each piece and move the points to affect the movement of voronoi pieces with a copy node. Now, the effect I'm trying to achieve is that when the particle turns red, the particle stops moving, and the voronoi piece that the particle is driving stops as well (velocity becomes 0). The problem I have is, that if the particles are not moving (its just static voronoi cube) the switch to RGB works perfectly. But as soon as I add curl noise on particles or any movement, the RGB simulation messes up. You can see that in my .hip file when you go to - box_object1 - popnet1 and you visualise the "BROKEN_SIM" node (which makes the particle stop when they turn red). If you visualise CORRECT_SIM, everything works just fine. Could it be that the rest position takes the frame 1 position of voronoi and then messes up, because voronoi has moved? Does anyone have an idea what could I be missing? dropFreakingOut.hipnc
  19. Hey guys, I'm trying to create an effect, where spheres move from the centre and after a certain frame, they all fall on the ground after each other. I've created pop net which drive the movement of spheres. I've tried to achieve the falling of spheres in two ways: 1., force and collision in popnet - works nice, but the rotation looks funny when colliding with the ground + I can't come up with a way, how to make the spheres fall after each other (so they don't just fall on the ground at the same time) 2., rigid body for spheres - I can't find a way how to mix the velocity from pop with rigid body. What I did was, that put a switch node and after a given frame - pop driven spheres are invisible and the RGB spheres become visible, but I suppose that is a very nooby way of doing it There is a visible difference between these two ways, because the popnet driven spheres fall down nicely and the fall looks more natural. With RGB spheres you can see when the movement is switched. Is there a way how to take the velocity form the popnetwork for each particle driving the sphere and blend it with the RGB simulation somehow? Or in other words, could I make the rigid body simulation of spheres make look like the one I created with the popnet? Sorry if there already is a topic explaining this problem, but I wasn't able to find it yet. Thank you RGB_POP.hipnc
  20. Hello, I have a geometry created by "scattering" cubes over a surface. And now trying to apply forces on the cube in sequential manner (small groups of cubes get simulated one after another). Please see attached image. Right now, I am using a Box SOP (step animated) in mask field for activation of groups. However, it seems to be having some issues. Due to the mask being animated, once the activated bunch goes out of the box, they don't follow the settings in forces. I started to somehow fix it by setting box sizes or thinking that "nested masks" could help (if there is such thing). But then I may be looking into wrong method for this effect. I am reading about the Activate DOP to achieve this and looking for more suitable examples. The goal is to activate simulation on surface of cubes based on inclusion in some arbitrary shaped mask box (active if inside the box). The shape of mask box will be changing over time. Any help on this would be appreciated. Thanks **Note : I am at beginner level in Houdini. **
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