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Everything posted by Fireandsmoke

  1. Vector maths basics

    But how would you define the direction of the green vector, because without the point of A as a reference, how are we to know by reading the green vectors coordinates that the origin is the tip of A?
  2. I'm following recommendations to avoid use of the copy stamp SOP. I have a trail effect which I've created with a solver sop which I want to copy to points on a grid, using a forEach and a CopytoPoints. But I want to vary the randomise seed of each of my trails so they appear different. How can I pass on an attribute with a unique value per point which will "stamp" the trail, allowing me to apply a unique seed to each copy? Thanks for the advice. polyextrude_solver_foreach.hiplc
  3. Copy Stamping using the new ForEach workflow

    Thanks Andr1. This is a little different to what I was proposing which was to change the actual branching of each pattern, but is interesting nonetheless. I've been trying to decipher your hip, can you elaborate a little on what you are doing by isolating the back face and applying the pivot? I'm a bit lost getting that part. Thanks for providing that example. Thanks Toadstorm. I'm surprised by this, I would have thought it would be a common technique.. I suppose it is not a very efficient way of doing things.
  4. Copy Stamping using the new ForEach workflow

    Thanks David, nice video. I am familiar with those techniques for stamping static objects. Where it is not working for me is that I'm trying to copy solvers, and use the same technique to vary a seed which randomises the pattern of each trail. However for some reason, it doesnt work, all the trails still appear the same (see project file). Do you know why this may be? Also, I noticed in your vimeo comments you replied that you weren't sure whether for each loops are more efficient than stamping. I believe that whilst there may not be much gain just comparing to for each loops, the benefit comes from being able to use for each loops inside compile blocks, which are significantly faster. Jeff Wagner talks about it here at around the 45min mark:
  5. Using a Group Expression SOP I can find the last prim of my geo with @primnum==`nprims(0)`-1 If I want that selection to change randomly between, say the last 4 prims, why does the following not work: @primnum==`nprims(0)`-rand(@Frame)*4 Also, is the reason I require backticks for the nprims expression above because it is a hscript expression in a VEX context? Thanks
  6. Rand value in Group Expression

    anim, thank you! Exactly that. I was watching the geo spreadsheet totally lost as to why the grouping wasn't moving beyond the first frame. So if I were to summarise this into a rule for my future self, Hscript expressions, which must be used in backticks to work in a VEX context, will always only return a single value. If it's not too low level to explain, why is this?
  7. Rand value in Group Expression

    Thanks guys. So what I am trying to achieve is quite simple in theory but not working for me so far, and I think I can see why... I start with a box, which I run into a solver. Inside the solver I have a very basic setup which takes the previous frame into a Group Expression which randomly selects one of the last four prims, and then a poly extrude to extrude that selected prim. So the effect should be that the end of the object grows a new extruded face each time, like a twisty branch growing. Displaying the primitive numbers, I think I can see why this isnt working. For some reason when the extrude is running through the solver, it shifts the primitive numbers around every iteration. Whereas if I were to take a box and extrude it a few times manually, all existing primitive numbers hold their original position, and 4 new numbers are created each time you extrude and create 4 new polys. Can anybody explain the logic of why this is happening inside the solver? Thanks! polyextrudesolver_project.hiplc
  8. Rand value in Group Expression

    Thanks bhouse will give this a try tonight. Regarding the backticks, symeks post just mentions backticks need to be used when writing expressions in fields which expect hscript. This is Vex input so does this also apply as a blanket rule in Vex? Symek has confused me a bit, he categorises those expressions like npoints () as being different to Hscript, Ive always thought of those expressions as being Hscript expressions.
  9. Render Cd in Packed prims

    Thank you kindly!
  10. I have a grid with random coloured points, copy a bunch of cubes onto it using a copy to points and select "pack and instance". Why do all the cubes inherit the Cd and show it in the view port, yet when I render, they do not show Cd? How can I get around this? Thanks
  11. Hi, I've been struggling to work this out for hours, wondering if somebody can put me out of my misery and give me some direction. I basically have created a simple solver setup which grows a wiggly line using an Add and randomly transforming the position of the last point on the line. I'm trying to copy this wiggly line to points using a Copy to Points and For Each loop, but can not work out how to get the randomness of the line be different for every copy. I thought maybe I could create an attribute based on the iteration value which could be used as a seed, but it's not working for me. Would really love some input on this, Thanks a lot, much appreciated Growingline_Solver.hiplc
  12. Alembic geo not working with Boolean

    It was the conversion to poly that I was missing, thanks so much.
  13. I'm playing with this volumetric video capture (a mesh I'm importing as an alembic file - download at the bottom of this page http://www.depthkit.tv/demodata/) I'm trying to create a layered outline effect intersecting a stack of grids with the model and using the Seam operation of the Boolean SOP, but none of the boolean functions work with this mesh at all. Are there rules as to what kind of files play nice with the boolean sop? I tired exporting the alembic as a .bgeo but same issue.. Cheers
  14. That has worked, thanks very much!
  15. Hi, A little similar to a question below in this forum, I am trying to import a photogrammetry capture OBJ from Reality Capture into Houdini. The OBJ comes with 34 image texture (UV #1-6), each separated into multiple images, for example: u1_v1.jpg, u1_v2.jpg, u1_v3.jpg u2_v1.jpg, u2_v2.jpg, u2_v3.jpg u3_v1.jpg etc etc... Can anybody shed some light as to how I import a texture like this into Houdini? Thanks kindly
  16. Ink FX

    Thanks for clearing that up eetu. Had me well confused at the time! Really like your blog, thanks again.
  17. Erode text into smoke

    Hi, I'm trying to work out how I will erode a 3D font into a smoke effect. I cant find any tutorials online other than VAROMIX's disintergrate geometry tut, which is great, but I dont want to wipe my text away with a boolean intersection like that. I'd prefer to have it erode away with a noisey pattern. What would be a basic approach to this? So far I have made an animated noise map in COPs which I send to my shaders opacity channel, so I get an animated dissolving object. That works ok, but how would I now get my smoke particles to birth from the corresponding areas as they dissolve? My newb guess is that I need to use the noise COP to also drive an Alpha in a point VOP, but I'm struggling to work it out.. Any advice much appreciated, thanks a million
  18. Hi, I'm using redshift to render a camera moving through some clouds (static). The clouds are imported with a File node, as they were previously cooked out to disk. The volume is a reasonable resolution (vdbs are around 300mb each and Im loading 2 of them). I import the clouds with separate File nodes, and render using one RS light. The render itself is fast but at the start of every frame, it goes through a "extracting object/...filepath.vdb" process which lasts for > 10 minutes per frame before each frame renders. What is happening here and is there a way I can reduce this time? Also tried loading .bgeos and have the same problem. Cheers for any advice
  19. Great Tip, thank you! Agreed that a custom color to stand out would be very helpful.
  20. I've been doing some basic playing with particles by turning a grid into particles with some wind and curve forces. I like the look where I set the pscale to very small and push the count into the millions. But I find that particularly around the edges of the particle system it looks very flickery and noisy when rendered. I've been rendering in Mantra with fairly default settings, and usually 3*3 samples. I understand that my particles are probably only one pixel in size each and there is plenty of movement in my system, but wondering if there are any tips on making the particles look more cohesive as a whole rather than so noisy. Thanks for any advice
  21. Ink FX

    Thanks again Valdez, that explanation makes sense. What I was wondering though is in Eetu's .hip, how did he match color to ID because he did not do the same method as you suggest. He did not enable ID in the attributeCopy Dop, Attribute to Match. How else was it done?? I went through his project file many times but couldn't work it out.
  22. I have temporary access to a computer on loan which I'd like to run the second seat of the Indie License on. But I want to know if I'll be able to remove the license and transfer it onto a different machine once I have to give the loaner back. Anybody tried this yet and know if it's possible? Thanks
  23. Ink FX

    yes! Thank you that worked! Thank you so much Valdez, your help is greatly appreciated. The reason I did not find this is because eetu's project does not contain this setting. So Im curious how is he matching those IDs?
  24. Ink FX

    Thanks for the reply Valdez, I've just spent another hour combing through eetus hip, inside the attributefrommap SOP and then inside the VOP SOP, comparing to mine and cannot see where or how this matching ID exists. Would you mind kindly explain the steps precisely in this part? What do I need to do to match by ID? Thank you so much for your help, sorry for being so ignorant
  25. Ink FX

    For such a simple little effect this is giving me no end of headaches as a newb. I have tried to copy eetus example in making my own, but getting this problem where the texture scrambles after a few seconds. Any ideas? I'm lost!