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Everything posted by logix1390

  1. activate particle when its born

    Hello, I have a growing emitter which is being scattered with points as it grows. In the popnet, I am trying to activate my scattered points only when they are born. Only the points that are born should be simulated by the pop force. I am able to achieve this effect with a static emitter easily , but I am having trouble getting this to work with a growing emitter. I will attach my file for anyone who wants to take a look. Thank you! particle_activate_on_first.hip
  2. activate particle when its born

    Thank you Sepu this works. Yeah I think I was just confusing myself with the solver. Appreciate the time.
  3. high detailed nebula

    This is a better reference video: https://www.artstation.com/artwork/0gXbV
  4. high detailed nebula

    Hello, I have been trying to create nebulas that have this much detail as seen here : https://www.artstation.com/teunvanderzalm He is fantastic at creating nebulas in Houdini. My methods on recreating this were basically to create an interesting pyro simulation, advecting millions of points and then adding additional noise to it post-sim. I also play around with the pyro shader to get interesting looks when I combine the pyro and particles at render time... I am getting some really interesting looks, however I am still not getting the smaller, finer detail that he has no matter how high res my pyro sim, or how many points I advect through it. I add layers of noise to my particles after, and it still doesn't look right...I feel like im going around in circles. I was wondering if anyone had any tips for me to achieve such an amazing look . I feel like he could be using a custom pyro solver... not sure if I should just keep going with my methods until I get a better look. Any thoughts ?
  5. Hello, So, I have a bunch of small pyro caches that I copied on some points. I enabled stamp and pack geo on the copy. Is their a way I can easily randomize the density on each of the copied pyro cache? Nothing seems to work... Thank you
  6. Randomize density on copied pyro cache

    Thank you for the replies. Shinjipierre, i tried that, but it doesnt work with packed objects.. I need to pack them since I have 1000's of volumes.
  7. cutting a line procedurally

    sweet thanks for the help Noobini
  8. cutting a line procedurally

    Hello, I have a geometry base shaped like an L. I am trying to cut a line as in the picture below. The thing is that it has to be procedural in one way or another. I used a divide node, which cut me a line diagonally, as you can see. I need it to be cutting across instead. Any help would be greatly appreciated. I will attach my scene file for anyone who wants to take a look. Thank you base_divide_cut.hip
  9. cutting a line procedurally

    Thanks again Noobini, exactly what i needed! Im just wondering now what each sop is doing exactly. specifically the "polyframe" , "measure", and "sort". How does this achieve the proper cut ?? I notice that the "curvature" attribute is just giving me a value of 0 for each point. How is it using this information to achieve the end result?
  10. Orienting copied objects

    Thank you Neon, it works perfectly.
  11. Orienting copied objects

    Hello, So i have a roof and I want to make some wooden pillars on the inside of this roof. My method is to basically copy the pillars to the centroid line of each side of the roof. I know the copy sop looks at the normals for orientation so I made sure my normals are aligned the right way before I copy. However, The copy is still not respecting the orientation of the normals. I have been trying to figure this one out for 2 days now. Im sure im missing something easy here... I will attach some pictures and my scene file to show you what I mean. Thank you. pillar_orientation_roof.hip
  12. channel reference- addpoint function

    Perfect. It works now. Thank you Noobini
  13. Hello I have added a point using vex : addpoint(0, {0,0,0}); I want to create custom sliders for each axis of the point position: @P += {ch("xPos"),ch("yPos"),ch("zPos")}; But I get an error . I have no idea why this is happening. I will attach my scene for anyone who wants to take a look. Thank you add_point_channel_ref.hip
  14. Noise texture on Lava sim

    Hello,. I have a quick lava sim that I want to shade with a noise AFTER i import it. from dops.. I need the noise texture to stick with the particles as they move. After I import in the lava sim, I make my point vop and add the noise to the rest field. However, it turns black and nothing happens. I have rest fields enabled in dops. When i search this issue online, It's usually people working with uv's. Do I even need uv's to get a simple noise to stick to the particles after sim? I'll attach my scene for anyone who wants to take a look. Thank you lava_noise_rest.hip
  15. Understanding Ray VEX

    Thanks guys, I can tell this is a very deep topic. I definitely have a better perspective on it now.
  16. Understanding Ray VEX

    Hello, I am in the middle of doing a procedural modeling tutorial: http://lesterbanks.com/2017/03/procedural-modeling-houdini/ He creates a curve and manually rays it to the terrain using vex . The code is as follows: (the curve is in the first input and the terrain mesh is in the second input) vector rayD = {0,-100,0}; vector hittP, hitUVW; i@hitPrim = intersect(1, @P, rayD, hittP, hitUVW); @P = hittP; This works perfectly Now I am trying to understand what is going on here exactly and how Houdini is solving this . I searched for the intersect function in the help and found this: int intersect(int input, vector orig, vector dir, vector p&, vector uvw&) I guess what is confusing me is the "vector p&", and "vector uvw&" above and how that related to the vectors he created "vector hittP, hitUVW" . I am still a beginner in VEX ... If anyone can help me understand this, I would really appreciate it. I will also attach my scene file for anyone that wants to take a look. Thank you! Ray_VEX.hip
  17. Change color in VOPS

    I have a rather noob question ... I have red spheres copied onto a grid. I want to change the color to Blue using VOPS. after the copy.. I can do it in vex easily, but im not sure why it's not working in vops. I tried a few things... the set vector component seemed promising according to the help card, but i'm not sure how to use it exactly. I'll attach my scene file for anyone who wants to take a look. Thank you.
  18. Drag by Proximity -Particles

    Hello, So I have some particles flying around an animated sphere. I want these particles to slow down as it moves away from my sphere. I noticed in the preset vex expressions for drag it has a "Drag by Proximity to Point" expression. However, I am having a tough time understanding this... // Drag by Proximity to Point vector target = {0, 1, 0}; // Target position float dist = length(@P - target); // distance to target float radius = 2.0; // Effect radius dist = fit(dist, 0, radius, 0, 1); // fit to range airresist *= dist; -------- Question: vector target = {0, 1, 0}; <<<---- where exactly is this y value ? Is this y value in relation to my animated object ? How can I set my target to be the centroid of my emitter dist = fit(dist, 0, radius, 0, 1); <<<---- how is the distance and radius related in regard to a fit function ? I'm wondering if there is any easier way to get my particles to slow down as it moves away from my emitter and almost look like it is following my object. I know a pop attract will work, but it takes a while to get the correct settings.. Thank you
  19. Drag by Proximity -Particles

    Hi Sepu, Thanks for the tips, I think i got it working now.
  20. Change color in VOPS

    thank u sepu
  21. Change color in VOPS

    Sorry, here is the file. change_red_to_blue_vops.hip
  22. Glue Constraints not falling with gravity

    Thank you Dam, works perfectly.
  23. Hello, I have several floors of a building that I am destroying as part of a destruction project I am working on. I notice that all of the floors stay static in space and are not affected by gravity. It is weird, because all of my other elements (bricks, wood, concrete, etc..) simulate perfectly.. I even imported only one floor and that stays static in space as well. I was hoping the floors will all fall down and break based on how strong the constraint is.... It seems like the constraints are taking priority over gravity.. I will attach my scene for anyone who wants to take a look. Thank you. constraints_not_falling.hip
  24. Concave Geometry-Boolean Fracturing

    Hello , I have a fractured a box using the boolean method in Houdini 16.... It simulates perfectly when using convex hull for the collision. However, when I switch to concave , Houdini crashes every time. It only crashes when I have a mountain sop added to the grids that are cutting up the geo. If I turn off the mountain sop, it simulates perfectly with concave. I kind of fixed this by remeshing each piece in a for loop, however it is really slow and all my pieces look way different. I wanted to know, if there was an updated method for properly simulating with concave, specifically with Boolean fracturing . I am destroying a building, and corner pieces that involve all sides of the walls wont work well with convex hull so concave is needed for accurate collisions. Any suggestions, or tips would be greatly appreciated. I will attach my test file for anyone that wants to take a look. Thank you. rbd_convex_concave_rd.hip
  25. Concave Geometry-Boolean Fracturing

    Thanks guys, both methods worked perfectly. Appreciate the help.