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Juraj

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Everything posted by Juraj

  1. I AM DYSLEXIC

    Hello, I AM DYSLEXIC - a very nice student project I worked on back in 2015 just got published, I did FX for it, all in Houdini, then handed over caches to lighting and rendering guys (rendered in Mental Ray in Maya). I really like visual style and it was really interesting to do some effects for this style of animation. Enjoy Short breakdown: 00:48 - paper (cloth) sim, a proxy collision geo of hero character was animated and used for interactions 03:22 - RBD simulation advected by hand-drawn guide curves and underlying FLIP simulation, some VDB meshes for hill filling, procedurally generated pages between books with fake dynamics (even though they got totally lost in the renders)
  2. Juraj's playground

    I wrote a guide on writing simple node operating on OpenVDB volumes in HDK: Creating simple C++ OpenVDB node in HDK What it does is basically: the node will take a VDB volume as an input and point cloud, then at position of each point it will activate matching voxel in VDB volume. You can also check repository with the code: VDB Activate from Points
  3. Juraj's playground

    Hello community, I am creating this thread where I will be posting links to my tests, experiments, RnD's and other uncategorizable stuff. Also often I will include scene files so feel free to explore them and to learn how not to do things ...hope it will help somebody, somehow. Juraj
  4. Juraj's playground

    Compiling DreamWorks OpenVDB C++ nodes for Houdini on Linux and another guide - how to add DreamWorks OpenVDB nodes into your Houdini
  5. Juraj's playground

    Compiling C++ OpenVDB Hello World example using Houdini precompiled libraries on Linux - a quick guide, might be useful to somebody
  6. über slow

    I was just wondering about the same thing, it is quite slow from my side as well.
  7. Juraj's playground

    adding project files, it is a bit messy because it contains all my nodes for exploring the techniques and testing out things, but still might be helpful for some some paths are hardcoded but with a bit of fixing you can get it running gridless_selma.hipnc
  8. Juraj's playground

    added project files, note that in interaction_forces.hipnc I used a technique for calculating eigenvectors which was a bit overcomplicated, I updated the technique in curvature.hipnc but did not update the particle sim setup yet interaction_forces.hipnc curvature.hipnc
  9. Juraj's playground

    k_means.hipnc obb.hipnc
  10. Juraj's playground

    lit_sphere.rar
  11. Juraj's playground

    Project file for OpenCL and VEX raymarching. raymarcher_ocl_vex.hipnc
  12. Juraj's playground

    Inspired by couple of papers and Houdini tutorials I started playing with fractals and raymarching. Here are some of the results so far. EDIT: see the following post for the project file
  13. Hello, in Houdini 15 I was using hou.ui.selectFile() dialog to get user's input and I would process it further in python. I used the same function to let user select files or folders, based on the needs of a tool. Now I updated to 16 and the function does not seem to enable user to select a folder, it works only with selecting a file. Does anybody know if there is a way to select a folder in 16? I want to batch process files in a directory and I would like to use file browser dialog to let user set it. In worst case I could use hou.ui.readInput(), and to ask user to enter a path there, but this is super user-unfriendly Thanks, Juraj
  14. Pulse of Life

    Hello, now when it is finally published I would like to share you something I was working on during my first semester at the university. It is an university project done at Filmakademie Baden-Wuerttemberg and my role was Technical Director. Enjoy watching with loud sound and in HD Big thanks goes to our cool team, who did their best to finish this piece: Concept/Design: Alex Berweck Technical Directing: Juraj Tomori Film Music: Alexander Wolf David Sounddesign: Robin Harff Animation-­/ VFX-Producing: Vincent Waltan, Tina Vest Modeling: Mitja Öhm Director and Layout: Caroline Kießling FX & Simulation: Aleksej Skrypnik, Justin Braun Production Company: Filmakademie Baden-Württemberg GmbH Pipeline was centered around Houdini and Mantra and we really enjoyed the production of it. I did short breakdowns of a tools and workflows I developed for this project, you can check it here: https://vimeo.com/album/4471569 We used a lot of assets and relied heavily on instancing and I really liked how well Houdini suited into our pipeline, from fast viewport preview of packed disk primitives, to lightweight IFDs being constantly sent to renderfarm Also using digital assets enabled us to efficiently collaborate and transfer setups to the shots. Also big thanks to awesome people here at odforce, it was really great learning/help resource for our project. If you have any questions feel free to ask Juraj
  15. Hi, I tried to update to latest build 16.0.736 (linux), but it isn't working. I can simply select files, but when I select folder and click accept, nothing happens, selection is accepted only if I select a file. In 16.0.557 it works normally, but not in 16.0.600, 16.0.633, 16.0.736
  16. Selectively load volume from VDB file

    So, I just found out, that OpenVDB's Houdini implementation has a node for exactly this purpose From node's docs:
  17. Hello, now when I am loading VDB volumes with File SOP it sometime takes some time, especially with big volumes stored on network. I was wondering whether it is possible to load only specified volumes from a VDB file, for example to load only heat, to keep loading times slower. This would save a lot of time in situations where I am blasting all other volumes which I do not need directly after File node. I quickly checked docs and found that it is possible to firstly read the header to find out information about stored VDBs and then to load needed volume (in Reading and modifying a grid section). Any ideas if it is supported right now in Houdini implementation / or if there are any plans to add this? Juraj
  18. Pulse of Life

    Thanks, we also appreciate your feedback and help during the production
  19. simple vector problem

    Hi, you can compare angle between two vectors with dot product: the normal vector (v@N) and vector pointing from second point to the first one (v@difference = pt2 - pt1 , (pt1 and pt2 are positions of first and second point) ) and if angle is positive, then the second one is in front of, if negative, the second one is behind the first one. Pseudo code could look like it if (dot(v@N, v@difference) > 0) //second point is first else //first point is first
  20. Juraj's playground

    Hi, unfortunately I cannot share the whole setup. I shared as much as I am allowed in the blog post explaining the process of implementing this technique. Hopefully later I will be able to put it here, but not now.
  21. Hello, does anybody know how to render flat shaded scene from OpenGL ROP? I need to do some viewport renders and I would like to have the exact look as in the viewport when set to flat shading. OpenGL ROP renders out stuff in smooth shading, even if it is set to flat. Is it a bug, or I am doing something wrong. Thanks, Juraj
  22. OpenGL ROP and flat shading issue

    My bad, now I see, that I actually want to disable lighting component (specular) in the OpenGL ROP in the same way as I would do in the viewport when right clicking on lighting in display options toolbar. Edit I figured it out, after assigning a constant shader, then speculars go away, this viewport if too fancy for my needs
  23. Juraj's playground

    car_paint_shader.zip
  24. GLSL shader questions

    Hello, I would like to experiment with GLSL shaders in Houdini viewport a bit, but I had very little success yet As a simple thing I would like to create a "matcap" shader, I have this shader in mantra and it works well, but it is quite simple logic in it and I would like to try it out in GLSL as well. I tried two approaches for creating glsl shaders: New Operator Type - SHOP Type - GLSL Shader This approach does not give me any results, the default shader has quite complex code and in the viewport I can see only white color. I tried to modify couple of variables in the code to at least change color from white to red, but unsuccessfully Reference ogl_glsl_shader parameter on a shader pointing to shader.prog file which references to shader.frag and shader.vert This gives me results in the viewport and works quite well, however I do not know how to reference node's parameter value to the GLSL variables. I created those files based on examples in $HFS/houdini/glsl //fragment shader in vec2 matUv; out vec4 color; uniform sampler2D tex; void main() { vec3 base = texture2D( tex, matUv ).rgb; color = vec4( base, 1. ); } First question: how can I reference parameter on the node to the tex variable in opengl? When googling I found some examples which implied that only creating string parameter tex should work, but when running their example files I never got any result in the viewport. Second question: is this the correct workflow? How could I achieve the same thing with New Operator Type workflow? Do you have some simple examples of those nodes with basic shading? E.g. sampling a texture, using constant color... Thanks for any clarification, Juraj
  25. RGB to Kelvin

    Just thinking out loud - color of blackbody radiation can be represented by temperature in Kelvins, or RGB color it emits. So Kelvins to RGB mapping should be straight forward, but backwards it might be tricky, as a RGB value may not be present in blackbody radiation spectrum. If I understand it right, then this plot is showing Kelvin temperatures mapped to RGB colors. So solution that comes to my mind is to find a Kelvin value, which is closest to the given RGB value. One way would be to take an array of Kelvin values converted to RGB values and to find the closest match (based on euclidean distance). Or if array of Kelvin values is not dense enough, you can linearly interpolate between two closest points found. It is not very precise, but should be good enough for some cases. Also, one more fancy thing would be to compute the distance of given RGB value and Kelvin sample in Lab color space, because if I remember correctly, then distances in Lab color space match the best to the perceived difference in colors (Maybe it is some other space, you can look it up)
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