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Found 23 results

  1. Procedurally Set Pivot for object

    Hello, For now I have learned to centerize the pivot but I just wonder is there any way to procedurally position the pivot? Like in this scene I want to setup the pivot properly at the begining of each leaf Thank you for your time. Pivot_Position_Ask.hip
  2. Hello, Could anyone make a quick example how would you scale the down the UVs to a pixel point by each of the islands pivot points? Specifically, I'm trying to do this for the voronoi fracture pieces, so each of the pieces UVs get scaled down to a pixel Thanks in advance!
  3. Hi, this is my first post, sorry in advance if I get something wrong. So I have an alembic file which comes from a nCloth simulation in Maya where I used a tearable constrain to break the cloth and a transform constrain to pull it in one direction. I imported the alembic in Houdini to polish and refine it. I also used a transform node with $XMAX in the pivot transform to scale the whole thing after the simulation is finished (since it needs to scale to 0 after the simulation is over). Now onto my question, how can I keep the pivot (found with $XMAX) at the centre of the world at every frame? so that the simulation appears to "start and grow" from the pivot itself? In the .hip file you will see two transform nodes ad the end, in the first one I used the $XMAX to scale from one end and achieve the "disappear effect", the second transform just has $XMAX because I was testing how to do it. I attached my .hip file but unfortunately, the alembic is too heavy for my internet connection (which is really bad), sorry about that.. Thank you in advance for you time ballon_alembic_cleanup.hipnc
  4. Hi, i have a problem with glue constraints when I am doing second voronoi fracture. I dont know if this is an issue with pivot ? or something else. Can anyone help ? This one are correct, after first voronoi and then after for each loop I have this. I put in transform pivot tab $CEX,$CEY,$CEZ. Any help appreciate Thanks Mike glue_con_problem.hip
  5. Hi ! my friends who can help me solve this problem Thank you very much $CEX GCX BBX ? how to move the pivot.hipnc
  6. Hey, I simulated low res RBD pieces and am using a transform Pieces node to apply the position / rotation back onto the highres geo. To get the orientation / pivot for the template points input of the transform pieces node I used a "dop import" node which is set to create points to represent objects. But I had to bake out the RBD objects and animate on top of em in Maya and brought em back to houdini. I made sure the name attribute is exactly the same as on the highres geo again and packed it and currently just using an attribute wrangle to delete all prims so I only have points left. But those only come with P and name. How can I get the correct orientation / pivot back to align my highres geo correctly using the Transform Pieces node? Thanks guys!
  7. RBD sim and orient

    Hello guys. Recently i have run into strange issue. I have my packed objects, that have some orient on it. I need to feed them into the Bullet sim, problem is that if i have orient as attribute on the packed objects, my sim explodes on first frame (no intersecting geo), if i remove my orient, sim behaves as expected. so i have run my sim without the orient coming to bullet (renamed orient to keep_orient) and i thought i will just substranct+add them at the end to get correct orient values for my instancing i do as next step. Problem i have is that i was not able to get correct orient from it. Would someone able to explain me what would be necessary to do to make it work, or why bullet explodes with orient values? sorry i cant share any scene at this point. my whole setup is: points in the space, that have @pscale and @orient (random nodes), that goes into the grain sim, to make sure i have no intersections, then i do copy bunch of rocks onto those points which goes as packed geo into the bullet sim.
  8. After packing geometry, if I use this VEX snippet to edit the pivots I get predictable results: vector pivotOffset = chv("manual_pivot_offset"); vector pivotCentroid = primintrinsic(0, "pivot", @ptnum); vector newPivot = pivotCentroid + pivotOffset; setprimintrinsic(0, "pivot", @ptnum, newPivot); @P += pivotOffset; If I check "transform using point orientations" in the copy to points SOP and pack the copied geometry, the pivot will move according to the custom offset, but the object moves in a different direction. How can I solve this?
  9. Hello; In "Transform SOP" (or maybe other SOPs), is it possible to do a Per_Element scaling? I mean to scale each pieces based on it's bbox_center pivot, not based on main pivot (pivot defined in transform sop). In 3DSMax you have several option to scale selected pieces of a geometry which is awesome ("Use Selection center", "Use Pivot point center" , ... ). Thanks.
  10. How can I make local transforms in my primitives (either packed or unpacked) based on a custom pivot? Using MOPs or any other method. Thanks
  11. Hello I imported a geo into Houdini from Maya. I want to rotate it around its pivot, but the transform node doesn't respect the imported geo's pivot.It sets it to the origin. is there any thing I can do so Houdini uses the original imported pivot for transformation? thank you
  12. I am trying to set the pivot/center of a geometry to the center of a specific face, but I'm not sure what expression I need to get the location of a face, (or even how to copy the hard location of a vertex or center of a face). I attached an image to show what I am looking for (i.e. I am trying to set the origin to the purple box, and follow the face when I change the extrude distance) Thanks!
  13. Alembic packed geometry has a pivot intrinsic which sits on the centroid of each primitive. Is there a way to transfer an object from Maya and maintain the pivots that were set there? thank you and I was wondering if there is a way to
  14. I got really confused with multiple transform sops. I hate to ask such simplistic question, but the fact that I can't make it work means that I don't understand some fundamental concepts of Houdini. If I use them one after another, I thought that the second one would inherit transforms of the first one. in the example(Houdini 17 non-commercial) the first transform is animated and the second one is static(non-animated) but it is parented to the first one, so I expect it to follow the fist one, I mean the center of the second one should always be at the center of the first one, but it is true only if scale of the second one is set to 1. translate_scale_origin_q.hipnc
  15. Good morning dear community As well as we can get a bbox boundaries and centroid using as well $CEX, $CEY, $CEZ or centroid expression, exist the possibility to get "pivot rotation" related to world space? Tried conversion of acos to degrees using dot from Normal Vector but without successfully results. Take in mind it came from point deformed animation with constant shape (Menas bbox remain constant during the whole length animation) Thank you very much
  16. Hi guys, how can I edit the pivot to match a specific surface primitive or normal? I need to transform the arm of my robot in a specific way, so my pivot needs to be edited to match the surface normal. I already tried to edit it with " and ' but this only allows to move it but not to rotate it :/ Roboter.hiplc
  17. L-System Pivot

    Hello, Does anyone know a way to get the pivot point of each prim from an L-System? I'd like to use this for animating bends and rotations but I'm not sure how I would go about it. Logically I need to find the nearest point on the previous gen to the 0 point of each primitive but it must also take into account the transforms of the previous gens too. I looked in to matt estela's rotation matrices but this doesn't account for the previous gen's transforms. Any help greatly appreciated. http://www.tokeru.com/cgwiki/index.php?title=HoudiniVex#Rotate_prims_around_an_edge.2C_alternate_version
  18. Hey, a simple question here: how can I move an object to the pivot or a pivot to the center of an object; or an object to the center of the world? Got a case where the ship as well as the pivot are off. I need them both at the same place on object level.
  19. How does the pivot work when using the make transform Vop node? I am trying break down and figure out the function of the Make Transform node using python (Outside of any 3d software). The Translate is pretty basic as I can just place them into a matrix as they are x = m[3][0], y = m[3][1] and z = m[3][2]. For rotation I am using the following: def EulerToMatrix(Rotation): x, y, z = Rotation XM = M3([[ 1, 0, 0], [0, math.cos(x), -math.sin(x)], [0, math.sin(x), math.cos(x)]]) YM = M3([[math.cos(y), 0, math.sin(y)], [0, 1, 0], [-math.sin(y), 0, math.cos(y)]]) ZM = M3([[math.cos(z), -math.sin(z), 0], [math.sin(z), math.cos(z), 0], [0, 0, 1]]) return (ZM * YM * XM) I can then just pipe this information into the Matrix4. The problem I have now is that I cannot find any information that I can understand on how to apply the pivot to the matrix4. It's not as simple as just adding. I have attached a file that has the make transform that I am using to test against. The pivot seems to be linked to the rotation and so I am guessing it is related to the scale as well. Is there any way to break down how this pivot transforming works? MakeTransPiv.hip
  20. Hi I am trying to rotate a volume so it aligns with the original geometry. (align along x axis - convert to volume - revert back to original place) I tried setting the primintrinsic, but the pivot point is shifted relative to the original geometry, there is a way to specify the desired pivot for the matrix? Any ideas? Thanks) volume_rotate_v01.hip
  21. Xform pivot

    Hi, I'm trying to learn, but I sometimes find it hard to get answers from the doc (real good doc tho). here is what I'm struggling with at the moment: I want the pivot of a transform node to to be placed relatively to another object (in the same geo node). I need the pivot to be at XMIN in x axis, 0 in y axis, ZMIN in z axis. Easy. But I need the XMIN and ZMIN of another object. Can someone help me with the syntax ? thanks !
  22. Hi people... I got some serious vdb issues, where i got some vdb combining, tweaking,,,combining with other poly to vdb , etc. I have some xfroms on the geom before it gets converted to vdb and combined. It goes well for a while, i make keyframes on the xforms...and at some point on the vdb combine, the xforms stuff up and move out of position. It seems not to like xfroms up the chain, pre vdb conversion. I do get some odd warnings on some of the VDB combine, i was getting is a 'mismatch surface & surface value mismatch (0.025 & 0.075)' when both A&B vdbs are 0.025, (but gets fixed with a re sample before going in to the vdb combine on both A& B I also get a warning on 'surface & surface transforms don't match' on the vdb combine that stuffs up my transforms. Pain! I would try to do all my geo transforms then save an alembic and load back without extra xforms, but i do need to line this up to the millimeter, and I can't due to things going off ..... I am runnning 14.0.395 thanks in advance !
  23. hey guys i can't Center Pivot ( Rotation Angular velocity ) !!! could u help me Center Pivot_ Dop Network.hip