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j00ey

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Everything posted by j00ey

  1. New Year / New Showreel

    ...like I just got my hands on MS paint 3D! I'm re-rendering one of the clips atm, maybe I'll tone down the flickering a bit on the next version
  2. New Year / New Showreel

    I wanted to share my new reel - mainly Houdini but there's are also a couple of older Maya clips on there too. Any feedback very welcome...
  3. New Year / New Showreel

    @acey195 I took your advice and changed the beginning - probably more 80s looking than 90s now in fact but hopefully a bit more engaging. Thanks for the input, much appreciated.
  4. New Year / New Showreel

    Thanks for the comments - I did wonder about those bars actually, perhaps I should at least fade the video in under them a bit sooner. I'll have a think, don't want people to not watch it because of that...
  5. Distance from center in shops

    Does this do it? I got rid of the fit inside the shader so it's just outputting directly the distance from the centroid. I added a couple of image planes so you can check the result against an attribute calculated in SOPs. ShaderExample_edit.hip
  6. I've put a couple of examples of how to do this in the attached file. First way is using a solver SOP - that way is literally appending values to an array every n frames. The other method isn't technically appending values, it's just generating an array that gets longer every n frames. The advantage of doing it like that is that you can scrub the time line without having to cook the whole frame range. optical_with_circles_edit.hipnc
  7. HDA - Rope Maker

    Let me know if there's anything that doesn't work as it should..
  8. HDA - Rope Maker

    In case it's useful to anyone, here's an asset I made a little while ago and finally got round to documenting. It takes one or m ore curves and generates 3 levels of braided curves - first level coiled around the input, second coiled around the first and the third around the second. Additionally it can make a final level of 'hairs'. It supports animated inputs, and will transfer velocity onto the output but in many cases it's probably better to use a timeshift to generate the rope on 1 frame and use a point deform or similar. This also avoids texture jumping problems if using the supplied 'pattern' colour method. There's a fairly comprehensive help card with it and below is a demo video. If anyone finds bugs or problems, please let me know and I'll try and fix them when I have time... I'd be very interested to see anything anyone makes with it... TB__RopeMaker_1_0.hda
  9. Some DOPs RnD

    Here's another experiment from a while ago, never got round to putting it up at the time. It never quite worked as I hoped it would - maybe I'll revisit it some time and somethihg better will come of it. It's quite a simple idea - run a flip sim of whatever sort and sample the velocity of a 2D slice onto a grid of points. Then in COPs, starting with an image consisting of 0 to 1 horizontal & vertical gradients in the red and green channels [representing u and v], look up the velocities and advect the uv. On the next frame, read in the advected image and repeat. This image sequence is then read back onto a grid and used as its uv. I started with an image of some pebbles, I wanted to smear them around with the velocity of the FLIP sim but the shapes were already quite blobby and amorphous so the effect was too subtle. Had I run the sim for many more frames they it might have worked btter but I decided to switch to some more geometric shapes. As I said it never really went anywhere but in case anyone's interested in the technique I thought I'd put it up...
  10. Some DOPs RnD

    I thought I'd make a topic here to share some RnD I've been doing in spare time in case it's helpful to anyone, as I've been able to learn so much useful knowledge from others on here. I have a couple of other scenes underway that I'll put up once they're ready. They're not for any particular shot, more just the result of one thing leading to another... The first one is essentially a simple cloth sim a driven by an RBD sim, where some balls are attracted to a wandering point. I used a technique similar to generating a wet map to transfer some colour between the balls while they're touching which sort-of worked but ended up producing a lot more blue than anything else. Also for each point on the surface I calculate the difference between the average distance to neighbouring points during the animation and at the beginning, a sort of compression or stretch attribute and I'm using that to displace the surface first in SOPs, then also in the shader.
  11. 16.5 drums

    Oh great, I kept meaning to put persistent quickmarks on the H17 wishlist... someone must have done it for me
  12. 16.5 drums

    It appears to be out...
  13. Some DOPs RnD

    Thanks! I love the stuff you've been posting on here too - fantastic work!
  14. I figured this out, i guess I must have figured it out last time and just forgotten... I made a scene file in case it's useful to anyone. The pc file needs to go in a 'cache' subdirectory of wherever you download the scene to, ie $HIP/cache/butterfly_pts.pc butterfly_pts.pc displacement_pcLookup.hip
  15. Has something changed with the new H16 mat way of doing displacement that would cause problems with point cloud lookups? I have a shader [a modified classic shader] in which I'm looking up a point cloud to get some wetness and colour attributes and it works fine without displacement. As soon as I switch that part on though, all the wetness etc vanishes. I'm sure when I've done this before it just worked but I'm clearly missing something. I'm transforming global P from current to object space to do the pc lookup, I don't recall having to do any compensation there for the fact that the geo is displaced. Does anyone have any pointers..?
  16. Hi I'm having a problem with a cone twist constraint network. I'm setting all the axes per constraint in SOPs (goal_twist_axis, constrained_twist_axis etc) and I wanted to set the motor_target values inside a SOP solver in my DOP network but it's just not doing anything. I can set motor_enabled and that works fine. I've tried v@motor_target, v@motor_targetr, f@motor_targetry, nothing gets picked up. I can't find anything in the docs or online... Any ideas?
  17. Ah yes thanks! I was looking at the Geometry but of course until you set a value manually, there's nothing there. Much appreciated.
  18. I see - I just tried setting it with a quaternion and it's doing something! Thanks very much for the pointer. Where do you see that in the spreadsheet though to be able to tell you have to set it with a quaternion instead of a vector?
  19. Ah thanks - that's interesting, I'll try that. But on initial inspection, my goal_twist_angle etc attribs aren't converted to quaternion. Where are you seeing that happening?
  20. Well I'm actually not trying to achieve anything in particular, I'm learning some RBD stuff, specifically constraints and was looking into the cone twist. I think it may be a new thing but it does now have a motor capability and it does work globally [to be honest I'm still trying to understand what it's really doing] but per-constraint doesn't. I just copied the name from the related param field in the same way you can find the names like goal_twist_axis etc and indeed i@motor_enabled works but I couldn't work out the motor_target.
  21. Export animation data to JSON

    @f1480187's method is indeed much cleaner. Here's an updated file in case it's useful. basic_json01.hip
  22. Export animation data to JSON

    Thanks very much for the tip, I will look at that.
  23. Export animation data to JSON

    I made you a basic file to start you off - I'm not very advanced in python myself so don't take this as the proper way to do something, it's just a way... If you open a python shell and click on the 'Print JSON' button, you should get some JSON printed out. Look in the python module of the asset to see how it's set up. basic_json.hip
  24. Export animation data to JSON

    It depends on what the software you're reading it back in with wants. I was writing it out for a custom renderer so the developer gave me a template to use as a guide and I matched that, filling in the data from geometry attributes and transforms etc. I guess if you just want translation, rotation etc you can use worldTransformAtTime() to get the transformation matrix at a given frame, then use extractTranslates(), extractRotates() to get the values for each frame [or time step] that you want to sample. Check how the reader expects your JSON to be formatted and match that - eg [if my memory serves] I had to write the point positions as one long array of comma separated values that the reader parses in groups of 3 [x, y, and z], so that meant looping through the points, getting the positions, stripping off the brackets, appending to the array then putting square brackets around the array. The site I posted last time was very useful for checking I hadn't missed a comma or bracket somewhere. If you have experience with python I think it should be fairly straightforward, if not [like me] use the docs...
  25. Export animation data to JSON

    I've just been working on an exporter to write out geometry descriptions and animation data for a realtime renderer and found it was quite manageable using python, the thing that can get tricky to get right is the formatting - square brackets, curly brackets, commas etc. This site might come in very handy for checking your output : jsonlint.com
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