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catchyid last won the day on November 20 2016

catchyid had the most liked content!

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About catchyid

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    Khaled Abdelhay
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    Montreal, QC

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  1. Best/Fast approach for car wreck look (no sim needed)?

    Thanks Andrea, I got your idea until using volume gradient Not sure If I understand that correctly, meaning: If I have a VDB and a mesh, should I boolean them? or use volume gradient then boolean?
  2. Best/Fast approach for car wreck look (no sim needed)?

    Thanks Andrea I have a huge set of cars and the goal is to test whether it's possible to produce their wreck automatically, hence cannot sculpt manually. I am trying metaballs and so far they produce better results than just turbulence/anti aliased noise (but still sometimes, they produce intersecting pieces!). Another idea is to create deformers with metal like deformation (this is step is manual though), but then apply these deformers anomaly ! will see BTW, I've seen your car crash shot on youtube and it looks awesome
  3. Hello, I need to deform a car geometry to quickly create crash like deformation (plz, see attached). Note, I don't need a full simulation, just the final shape. What is the best approach? I tried to deform some parts of the car mesh using turbulence/anti-aliased/mountain noise, but it did not look right! Another idea is to use vellum (or bullet with soft constraints) to simulate metals and hit the car by random objects, but I am hoping for something faster. Any ideas? Thanks,
  4. what is du/dv in vex?

    Thanks, I found out about this in a different post My plan now as Christoper said, is to compute them shading context then "somehow" import them in SOP context...
  5. what is du/dv in vex?

    Okay, I think I need to read a little bit more about shaders in Houdini because I never used one Thanks for the hints Christopher
  6. what is du/dv in vex?

    Thanks! I am am still getting 0s when I read @dPdv (whether from points or vertices). I read in another post this @dPdv is only defined in surface context and not SOP context? Maybe that's why... https://www.sidefx.com/forum/topic/56676/ Update: I found a surface context @ https://www.sidefx.com/docs/houdini/vex/contexts/surface.html but I am not sure how to expose it or use it in sop context ?!
  7. what is du/dv in vex?

    Nice, but is it defined already for each point in a sop context? I've tried the following functions calls in SOP but it returns 0: v@dd=@dPdv; //I assumed maybe it's defined automatically like @N v@dd= primduv("/obj/mlb/x", @primnum, _uv, 0, 1); Thanks in Advance
  8. what is du/dv in vex?

    Hello! Urgent question I have uv map on points. In the uv space, I want to compute tangent du/dv in vex but I am not sure which vex function to use? To be more specific: I want to set dv=0.0001 (ie. go up a little bit in v direction) and compute du (i.e. the corresponding change in u). My end goal is to: for each 3D point, what its new position if I moved its uv in dv direction (maybe it's called dPdv)? Thanks
  9. Exporting Transforms to Alembic

    Man! Once more, your effort is much appreciated I will investigate more, but at least now I have enough leads
  10. Retime simulation

    I know retime node has improved in Houdini 17.5. I think you can simulate normally (i.e. realtime scale) then use retime node to speed up or slow down (you might need more substeps to help retime if it needs more data for slow part)
  11. point count is always changing, hence using @ptnum for any randomization will always give new result on each frame...try to find an invariant that will always be the same (I know this has not answered your question , sorry ) . I've tried using origpt instead, did not look right though, but I think it should be used as a starting point. Also, another idea (which is slow and inefficient) is to use to use the last frame of the animation where you have the full tree and assign pscale based on origpt and use transfer attributes to transfer pscale to the dynamic points (but again, I am sure it's easier to use origpt in the first place...)
  12. Exporting Transforms to Alembic

    @Thomas: thanks for input, will investigate "AlembicRef" as I never heard about it before! @Jo: sorry, I totally lost you here, can you elaborate more, I did not get what curves has to do with the orientation? and how it's related to a mesh?
  13. Hello, My Python experience is rather limited here, so I know my question might be so basic! I am running Houdini 17.5 on Ubuntu. I need to write some tools for Houdini, so my first assumption is that I can just run the default python2 interpreter and import hou, however when I do that python interpreter crashs (first complains about jemalloc library then crashs). So my second guess is to run the python interrupter that comes with Houdini and then import hou, this time, it does crash but still complains about jemalloc library? Now, I go directly and run hython and import hou and things seem to work nicely (i.e. no crash, no complaining about jemalloc). My questions: 1-I, i.e. the company I work for , have a production environment that already uses the default python, how other TDs integrate hou in a company pipeline without requesting to change the interpreter to hython? 2-Why SideFx ships it's version of the python interpreter? is it special? is it different than the default python interpreter? OR is it just to eliminate any external dependencies? As I mentioned above, when I used the shipped python and imported hou, I got still jemalloc warning too! Thanks
  14. Hi, Simple question! "UV Texture" sop node has many projection types (e.g. Orthographic, Polar,...). One type is "Row & Columns", I've tried to use it but I did not understand how it works! Does anybody have a simple example or explanation what it means? The documentations says: "The U coordinates are placed along rows and the V coordinates along columns", but I did not understand it! Thanks