Welcome to od|forum

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.


  • Content count

  • Joined

  • Last visited

  • Days Won


Community Reputation

12 Good

About catchyid

  • Rank

Personal Information

  • Name Khaled Abdelhay
  • Location Montreal, QC

Recent Profile Visitors

500 profile views
  1. Hi, I have particle simulation where I write a vex code like this : @pscale = rand(@ptnum), then I import the particles in a geometry node (using DOP IO) and use Copy SOP to replace the particles by spheres. I can see that the incoming particles @pscale is used to scale the spheres, but @Cd is not used?? Why is that and how to change the colors of sphere using the incoming particles @Cd Thanks...
  2. Hi, This is a very general question and I am looking for some ideas/hints/directions. In summary, I need to simulate what happens when horses run in desert, i.e. at each foot step ground particles rise up then fall slowly (maybe with some disturbance too). I am not sure what the right way to simulate this effect is: this is not particles simulation because the effect should look like a contentious volume and not particles, however it's not also smoke simulation because particles might fall quickly on the ground, i.e. they won't suspend too much in the air flow/turbulence created. I "think", maybe a particle simulation should be created and use it as a smoke source, but again, the smoke simulation must be configured to fall down quickly?! BTW, the same "effect" occurs when you drop a heavy box on the floor, when car wheels go very fast, etc. Any ideas will be appreciated
  3. Hi, In a VOP node (plz, see attached), I want to copy the Normal attribute from the second input and copy/connect it to the V attribute of the output. I only have the second input plug, but I am not sure which nodes to use to extract the Normal from the incoming geometry? Thanks
  4. have you checked the tutorials below, I "think" they could help...
  5. the link below might help you (it's been included twice! sorry, could not find a way to remove one copy!) houdini_collison -smoke problem
  6. Hi I am by no mean an expert Houdini user, but I think the kind of questions are too "technical", MAC Vs Voxel, No Slip Conditions, Eulerian or Lagrangian What are using Houdini for? Is it for Visual Effects or for engineering purposes? From your questions, I think they are oriented more toward Fluid Mechanics engineering (artists would simply diffuse temperature or velocity but won't care how it's it being computed). Finally, I don't think you will find C++ source code for solvers because these are SideFX code and they won't share it...
  7. Thanks Did not know about polyBridge Don't have 16 license ...
  8. Hi, I have two spheres, one bigger a little bit from the other. I use clip node to cut both spheres. I want to fill the gap between the two spheres but I don't know how ? plz see attached, basically the I want to create a mesh corresponding to the green lines. It should be simple! When I use polycap node, it fill the entire bottom, not just the gap between the two spheres... shell.hip
  9. Hi, When I create a digital asset, I go to Scripts->OnCreated() method and write some python script to change some parameters in the newly created digital asset, HOWEVER, I don't know the name of the asset, hence I don't know the path to any node inside the digital asset? When I type hou.pwd(), I get "obj"... Thanks, onCreated.hip
  10. Hi, I am developing an Explosion HDA, the goal is to create a black box with easy to tune parameters needed to configure the explosion. Since it's my FIRST Houdini Digital Asset I am designing, I have some broad question: Should I design as OBJ asset or as SOP asset? >At Obj level, I can benefit from translation parenting hierarchy but I think I am limited only to one input and one output and they must be used for transformation parenting only. >At SOP level, I can have multiple inputs/outputs but the HDA needs first to create a Geometry, delete the default file node, create my HDA, I could read multiple inputs and produce multiple outputs (but do I need them in the first place?) I know this is a very generic question, and it's more like a personal preference thing! But since I am just starting I am not sure if there is better approach than the other? Thanks
  11. Hi, >If I create a subnet/HDA in a /obj level, it will have by default 4 inputs and 1 output. >If I create it in /obj/geo, it will get 4 inputs and 4 outputs. (A) Why does the number of output differ with respect to context? I "think" in the /obj level, there should be exactly one input and one output because this represents transformation hierarchy information? what does it mean to have multiple parents at the /obj level? (B) I can use hou.node.inputs()[index] to get the input @ index. BUT how to say that a certain node is the 3rd output, for example? Thanks,
  12. [I got the answer on https://www.sidefx.com/forum/topic/49249/?page=1#post-222465] Hi, I've created a digital asset for an explosion, it simply hides the pyro simulation network and exposes simple parameters such as buoyancy, smoke dissipation. I want to allow the asset users customize some animation curves such as “gasrelease” (which is defined in the pyro solver). This seems problematic because: a-If I keep the animation inside the digital asset network, then this animation curve is considered part of the digital asset and it will be locked by default. The only way to edit the curve would be to unlock the digital asset and save the file, but this is bad because users might save the new asset definition and replace the default one, plus it's not practical to ask users to unlock the asset each time they want to edit it! b-If I keep the animation as an external new parameter (i.e. use the type interface to add a new parameter and add the animation curve to it), for some unknown reasons it won't get saved as part of the digital asset definition! i.e. even If create a new parameter and create some key frames then save the asset type, the next time I create a new instance of the asset the animation curve will be lost, i.e. will be constant value… Okay, I am not sure what I am doing wrong, but this seems like an easy thing to do but yet I cannot accomplish! All, what I want to do is to create an initial animation curve for the gas released parameters and then allow users to change it if they wish? Thanks
  13. Hi, I think the way described the problem is too complex...I posted the question on https://www.sidefx.com/forum/topic/49244/ but in a very easy to reproduce steps and description In summary, animated channels are not stored in the digital asset if a parameter got promoted!? i.e. if you instantiate the digital asset, you will find the animation is gone?!